( CNN ) -- Mourners packed church pews Tuesday at a memorial service for seven victims slain in a shooting rampage at a small religious college in Oakland , California . `` We realize that at this time we have to draw together , uniting for peace , praying for peace in our city , and praying to stop the violence , '' said a woman who introduced various parts of the service . Meanwhile , authorities continued searching for the weapon a gunman used Monday when he killed seven people execution-style at Oikos University . Accused shooter One Goh gave some details to investigators about Monday 's attack , but refused to say where he disposed of the gun , police said . Investigators had narrowed their search for the weapon and were combing a shoreline park area Tuesday , police spokeswoman Johnna Watson told reporters . Forensic investigators were still at the scene of the shooting Tuesday , she said . Police plan to present the case to the district attorney for possible charges sometime this week , she said . `` It 's a large investigation . We want to be thorough , '' she said . Goh was being held Tuesday in Alameda County 's Santa Rita Jail pending an initial appearance in court this week . The 43-year-old former student at the college `` does not appear to be remorseful at all , '' Oakland Police Chief Howard Jordan said . Police : Suspect was angry over college expulsion . Goh told authorities that he was upset about being expelled from Oikos University this year , Jordan said . Investigators believe Goh walked into the single-story building housing the university Monday morning , took a secretary hostage and went looking for a particular female administrator , who was not there , Jordan told CNN . Goh took the secretary into the classroom , but when he realized the administrator was not there , he shot her and ordered the students to line up against the wall . Not all of them cooperated , Jordan said , and so he began shooting . `` I 'm going to kill you all , '' the gunman said , according to CNN affiliate KTLA . `` This was a calculated , cold-blooded execution in the classroom , '' Jordan said . The suspect `` just felt a certain urge to inflict pain on them , '' he said . After the shooting , the man left the classroom , reloaded his semiautomatic weapon and returned , firing into several classrooms , Jordan said . He ended his rampage by driving off in a victim 's car , police said . In all , seven people were killed and three were wounded . `` This happened within minutes , '' Jordan said . `` We do n't think the victims had any opportunity to resist , any opportunity to surrender . '' The suspect was arrested a short time after the shooting , when he surrendered to police at a grocery store in the Oakland suburb of Alameda , Jordan said . Goh offered no resistance when arrested , Jordan said , and was `` very cooperative , very matter-of-fact , very calm . '' Under questioning , Goh `` remembered very good details '' about the incident , he said . `` He planned this several weeks in advance , '' Jordan told KTVU on Tuesday . `` He was so upset he went out and purchased a weapon and had every intent to kill people yesterday . '' All three of those wounded were released from Oakland 's Highland Hospital on Monday night , spokeswoman Monique Binkley Smith said Tuesday . Oakland Mayor Jean Quan condemned the violence . `` No American mayor wants to have this situation , '' she said . `` It seems over the last decade , we 've gotten used to seeing senseless mass killings like this , and we 'll have to question the availability of guns and the need for other services in our community . '' Investigators have determined that the gun they believe Goh used was obtained legally in California , but details about the weapon 's purchase were still under investigation , Watson said . Harrowing descriptions of chaotic scenes inside and outside the college emerged Tuesday . Audio recordings of police radio exchanges released Tuesday include a dispatcher describing reports of shots coming from inside the building . `` People are running out , screaming , '' she says . `` There 's a female bleeding down on the ground , face down on the concrete , '' a dispatcher says . An officer at the scene describes a man who has a gunshot wound to his head . `` We were able to extricate one body , a victim from the building , the victim still has a faint pulse . We 're waking her up now , '' another officer says . Art Richards told CNN he was on his way to pick up a friend and thought the commotion outside the school was caused by a car accident . Then , he said , a woman emerged from bushes and told him she had been shot . `` I was kind of mind-boggled , '' he said , but the woman showed him her arm . `` She had a good little piece , a chunk of her arm , missing . '' Police handcuffed one man outside the school , but the woman told authorities he was not the shooter , Richards said . `` Right after that , close to seven , eight , nine shots rang out , '' he said . `` Everybody got down . The police took cover . We took cover . '' A few minutes after that , the first body was brought out , he said . `` They were just pulling out bodies after bodies . '' Brian Snow said he was at a nearby credit union when shots rang out . `` I went outside and the cops were coming and like 'Do n't move , do n't move , ' and it started getting chaotic . ... A pedestrian came out with a bullet hole , '' he said . Meanwhile , inside the college , survivors hid behind locked doors or desks as gunfire erupted . Tashi Wangzon said that his wife , a student there , heard the shots , then locked the door to her classroom and turned off the lights . `` The man with the gun later came toward the room and , at the time , he fired several rounds at the door , '' Wangzon told KGO . `` Then he left ( when he thought nobody was there ) . '' Lucas Garcia , who was teaching an English class at the college when the rampage began , told KGO that he counted about six gunshots from a nearby nursing classroom and heard someone yell , `` He 's got a gun . '' Garcia said he got his students out of the building while the gunfire continued . What is Oikos University ? The college caters to the Korean-American Christian community but also has students from diverse backgrounds . It offers degrees in theology , music , nursing and Asian medicine , according to its website . The victims of Monday 's shooting ranged in age from 21 to 40 and were from countries including Korea , Nepal , Nigeria and the Philippines , Jordan said . With the exception of the secretary , all the victims were students . Of those killed , six were women and one was a man , but Jordan said investigators do not know whether Goh was targeting women . Quan , Oakland 's mayor , said most of the victims appeared to be from the city 's Korean-American community , and the city was working to find multilingual counselors to help survivors . Community and faith leaders were scheduled to attend Tuesday 's memorial , and they hope to develop a strategy for dealing with the situation , said June Lee , executive director of the Oakland-based Korean Community Center of the East Bay . `` We 're looking for a way to help the families and the community that are impacted by this incident , '' she said . Civic and church leaders will try to come up with a community strategy to deal with the tragedy , she said . But she stressed the importance of not stigmatizing Koreans or Asians . `` This is all new to us . We do n't want to stigmatize whatever the issue is . ... We need to identify the issues first , '' she said . CNN 's Michael Martinez , Sara Weisfeldt , Matt Smith , Alan Duke , Paul Vercammen , Dan Simon and Augie Martin contributed to this report .
NEW : `` We have to draw together , uniting for peace , '' a woman says at service . Forensic investigators are at the scene of the shooting . Police are searching for the weapon the gunman used . The shooter is believed to be in his early 20s and was wearing all black with long hair.