Another man was in the car with Walter Scott when he was pulled over for having a broken tail light on his Mercedes, it has been revealed. Police have not disclosed his identity and family do not know who he is, but a police report confirmed the man was detained with Scott and put in the back of a police car, according to CNN. The man, who is not a relative, could be able to shed light on what happened between Officer Michael Slager pulling the pair over - and the beginning of the bystander video which shows Scott being shot dead. The 33-year-old patrolman has been charged with murder after 50-year-old Walter Scott was gunned down last Saturday in North Charleston, South Carolina. It has also been revealed that the officer was allowed to stay with the force, despite being the subject of a complaint that alleged he used excessive force on an unarmed man. Police are now reviewing the earlier case in light of the shooting of Mr Scott. Patrolman Michael Slager calling colleagues on his radio after shooting dead the unarmed father-of-four Walter Scott . Officer Michael Slager, pictured left in his police mugshot, has been charged with the murder of 50-year-old Walter Scott, right . Eyewitness accounts said Scott was involved in a brief scuffle on the ground with the officer who pulled his car over for having a broken tail light. Mr Scott can be seen being shot five times in the back as he ran away from the armed officer in video footage that was captured on a mobile phone at the scene. The incident started at 9.53am when officer Slager radioed into his control saying that he was pulling over a grey coloured Mercedes. Minutes later he appears out of breath as he describes chasing a suspect on foot, who he says is black and wearing a green t-shirt. This is followed by a period of no contact from the patrolmen, despite colleagues en-route to assist asking for his location. Slager then makes a further frantic call to dispatchers at 9.38am after firing eight shots at Mr Scott. 'Shots fired. Subject is down. He grabbed my Taser,' After shooting Mr Scott, Slager can be heard telling his control: 'I need to secure my vehicle.' A second officer, named as Clarence Habersham, then uses his radio to report that the victim has gunshot wounds to his chest, right side, and backside. Slager, 33, who is white, initially defended his actions, saying he feared for his life after he alleged Mr Scott had wrestled his Taser from him during a scuffle. But four days later, anonymous cellphone footage emerged that contradicted his account of events. The video showed the officer firing eight shots at Mr Scott from around 20 feet away while he had his back turned and was fleeing. The officer draws his weapon as Mr Scott, 50, breaks free and starts to flee from the scene . The officer fires off eight shots hitting the fleeing father in the back five times . Mr Scott collapses to his knees after being struck after shots were fired . Slager then handcuff's Mr Scott's lifeless body before he allegedly appears to tamper with the scene . Slager, 33,  initially claimed that he feared for his life after Mr Scott wrestled his Taser from him in a scuffle . Sagler then cuffed Mr Scott's lifeless body and was seen dropping an object - possibly his service-issue Taser - by his side. In the video filmed by Feidin Santana there appears to be no evidence of Mr Scott getting hold of the officer's Taser or using it against him. 'I remember the police [officer] had control of the situation,' said Mr Santana. 'He had control of Scott. And Scott was trying just to get away from the Taser. But like I said, he never used the Taser against the cop.' Officer Slager was charged with murder on Tuesday and now could face the death penalty. Today Mario Givens revealed how he made a complaint about Slager in September 2013 and claimed the shooting of Mr Scott could have been prevented. He told how he was awoken before dawn in September 2013 by the patrolman, who was banging on the front door of his family home in North Charleston. Givens, who is also black, said he cracked open his door and asked the officer what he wanted. 'He said he wanted to come in, but didn't say why,' said Givens, now 33. 'He never said who he was looking for.' Officer Slager, 33, can be seen on video holding an object - possibly his Taser - after he shot dead Walter Scott . Officer Michael Slager was caught on video tape on Saturday picking up an object - possibly his Taser - from where the confrontation started with Walter Scott and appearing to move it over to the father-of-four's dead body . Then, without warning, Slager pushed in the door, he said. '`Come outside or I'll tase you,'' he recalled the officer saying as he burst in. 'I didn't want that to happen to me, so I raised my arms over my head, and when I did, he tased me in my stomach anyway.' He said the pain from the stun gun was so intense that he dropped to the floor and began calling for his mother, who was also in the home. At that point, he said another police officer came into the house and they dragged him outside and threw him to the ground. He was handcuffed and put in the back of a squad car. Though initially accused of resisting the officers, Givens was later released without charge. Angered by what happened, Givens went downtown to police headquarters the following day and filed a formal complaint. He and his mother say several neighbors who witnessed what happened on the family's front lawn also contacted the police, though they say officers refused to take their statements. Asked about the 2013 incident, North Charleston police spokesman Spencer Pryor said the department now plans to review the case to see if its decision to exonerate Slager was correct. 'It could have been prevented,' Givens said of Scott's death. 'If they had just listened to me and investigated what happened that night, this man might be alive today.' Authorities refused to say on Wednesday whether other police officers will be charged in the cover-up of an unarmed black father's fatal shooting by a white cop. North Charleston Mayor Keith Summey would not answer questions on the involvement of other members of the force in the killing of Walter Scott, 50. The 33-year-old patrolman, who is white, initially defended his actions, saying he feared for his life after Scott wrestled his Taser gun from him during a scuffle when he pulled him over for a broken brake light on Saturday morning. North Charleston Mayor Keith Summey (pictured left) refused to say whether other officers were involved in the fatal shooting of unarmed black father, Walter Scott, on Saturday. Police chief Eddie Driggers avoided some questions but did say he had been sickened by video of his officer shooting the man dead . Four days later, anonymous cellphone footage emerged and blew Slager's story wide open. The video showed the officer firing eight shots at Scott, a father-of-four, from around 20 feet away while the man had his back turned and was fleeing. Sagler then cuffed Scott's lifeless body and was seen dropping an object - possibly his service-issue Taser - by his side. The cop was charged with murder on Tuesday and could face the death penalty. During a chaotic press conference on Wednesday, demonstrators grew angry after the mayor took over questions directed at Police Chief Eddie Driggers who stepped back from the podium. Mayor Summey refused to answer questions on other cops' involvement, citing an independent investigation underway by the South Carolina Law Enforcement Division. Slager was fired one day after his murder charge but his wife, who is eight months' pregnant, will still receive insurance from the city until after her baby was born because it was the 'humane thing to do', the mayor said. This as the FBI and the Justice Department's civil rights prosecutors announced on Wednesday there would be a federal probe . Chief Driggers told the press conference that he was 'sickened' by the video and had watched it only once. No other officers had seen what happened at the shooting scene, according to Driggers. When asked why no one had performed CPR on Scott, Driggers then said he believed one cop had taken off Scott's shirt and tried to perform life-saving measures. Driggers said that he had spoken to Walter Scott Sr 'father to father' during a visit to the grieving family's home.
Mystery passenger was detained when he and Scott were pulled over for missing tail light .
Recording of patrolman Michael Slager's radio call to colleagues released .
Officer shot dead unarmed 50-year-old black father Walter Lamer Scott .
Slager can be heard telling dispatcher 'he grabbed my Taser' after shooting .
No indication Scott had ever had the officer's Taser or used it against him .