Crime Stoppers offers record reward in unsolved slaying of Iranian medical researcher Crime Stoppers Gelareh Bagherzadeh was shot outside of her home in Houston on Jan. 16. Her killing remains unsolved. Four months after Iranian-born medical researcher and activist Gelareh Bagherzadeh was gunned down in her car just yards away from her family's home in west Houston, authorities are hoping the offer of a sizable cash reward will help solve her killing. At a press conference Tuesday, the Houston chapter of Crime Stoppers announced it was increasing a cash reward to $200,000 for information leading to an arrest or charges in the case. It's the largest cash reward ever offered for a Crime Stoppers tip not only in Houston, but in the nation. "We don't want to wait for justice in this case," said Katherine Cabaniss, executive director of Crime Stoppers of Houston. Houston Police Sgt. J.C. Padilla said investigators still have no motive in Bagherzadeh's slaying and haven't ruled anything out. "The more we talk to people, the more we realize we need the community's help," he said. The 30-year-old Bagherzade was shot to death Jan. 16 while in her car, just yards away from her family's townhome in the well-to-do Galleria area. Police said at the time that Bagherzade was on her cellphone talking to her ex-boyfriend when someone outside the car shot her in the head through the passenger-side window. Crime scene photo of Gelareh Bagherzadeh's car, which crashed into a neighbor's garage door after she was fatally shot on Jan. 16 in Houston. The boyfriend told police he heard a loud thud and then a screeching noise. The victim's car crashed into a neighbor's garage door. Bagherzadeh moved to the U.S. several years ago and was studying molecular genetic technology at the University of Texas M.D. Anderson Cancer Center in Houston. Bagherzadeh was known for speaking out on behalf of Iranian women's civil rights. She was an active member of SabzHouston, a Houston-based group that was formed to protest the 2009 election results in Iran. The group contends the results, which declared President Mahmoud Ahmadinejad the landslide winner, were a sham. Bagherzade's slaying is perplexing because her purse and other belongings were left untouched in the car, and she had no known enemies. Police have said there's no evidence she was shot because of her Iranian activism, but that hasn't stopped a slew of unsubstantiated rumors from surfacing online that she was assassinated -- by Iranian government agents, by Israel's Mossad intelligence agency or by some other nefarious group. "It has been four months since my sister was senselessly killed behind our house," Ali Bagherzadeh, the victim's brother, said at Tuesday's press conference. As a community we should be outraged at the loss of a talented and beautiful person. The previous largest reward offered by Crime Stoppers was $100,000 for tips in the 2003 bludgeoning deaths of four young people in the Clear Lake area, also in Houston. Someone came forward in 2006 with a tip that helped solve that case, Cabaniss said. The cash reward in that case was offered for three years. The significance of that is that we recognize that sometimes it takes time for the person who knows who the shooter is to make the phone call that solves the case," Cabaniss told msnbc.com. We are hoping that in this case it doesn't take years for justice to be served. We remind the person who knows who the shooter is that one phone call today is worth $200,000. One name, one shooter, $200,000. Crime Stoppers is a nonprofit group that offers cash rewards to people who provide anonymous tips that lead to an arrest of people responsible for a crime. The first Crime Stoppers program was formed in 1976 in Albuquerque, N.M. Today, there are Crime Stoppers programs across the U.S. and around the world. The organization says that it has paid more than $92 million in rewards and that its tips have led to nearly 612,000 arrests. Anyone who has any information about the Bagherzadeh case is urged to call the Crime Stoppers hot line at (713) 222-8477 or submit tips online at www.crimestoppers.org. Tips can also be sent by text message: text TIP610 plus your tip to CRIMES (274637). All tipsters remain anonymous.