Friends and family gathered at the Second Baptist Church to remember Gelareh Bagherzadeh, the 30-year-old Texas medical student shot to death Sunday while driving near the Galleria.

Her friends described her as a "loving person" who had a bright future and big dreams. Now her family is asking the public to help find her killer.

Houston police said Bagherzadeh was killed on Augusta Drive near Sugar Hill Drive late Sunday.

Bagherzadeh's body was found inside her running car, which crashed into a garage, detectives said. She had been shot in the head through the passenger's side window, police said.

"When the officer arrived, the car's tires were still spinning," Officer J.C. Padilla said. "He had to reach in and turn off the motor."

Bagherzadeh's car was found at the back of the town home complex, and police said she had driven past her parents' home near the front of the complex.

"We don't know if she was being followed at the time," Sgt. Richard Bolton said.

Investigators said Bagherzadeh was a graduate student studying genetic research at M.D. Anderson.

"My family is devastated," said Bagherzadeh's brother, Ali. "It's very hard. I can't see my parents ... I don't want to see any parents be in this situation."

Officers said Bagherzadeh's ex-boyfriend was on the phone with her when he heard what may have been the crash and gunshots. He was questioned, but is not considered a suspect.

Police also spoke with the man who was her current boyfriend and friends, but they want to talk other people, including a friend she said assaulted in her in February 2010. According to court documents, Bagherzadeh said she was assaulted in the man's car, and he grabbed her hair and forced her to kiss him. The case was closed because of insufficient evidence.

Bagherzadeh was part of Sabaz Houston, a local Iranian organization that supports the green movement against the current Iranian government. Her friends describe her as sweet and smart.

Detectives said they are coordinating with the FBI. They said they have no reason to believe she was politically targeted, but they don't want to rule anything out.

"We're looking into that possibility, but there is no indication that it's a hate crime," Padilla said.

Bagherzadeh's purse and cellphone were still inside the car, so investigators are not sure what the motive for the killing may be.

Detectives reviewed surveillance video from a neighbor's home, but it did not reveal any clues.

"We're going to review it again, look at it closer, to see if it shows anything," Padilla said. "This is probably one of the most difficult cases because we don't have a motive."

"We need to get these people off the streets," Ali Bagherzadeh said. "She always asked me, 'Why people can't be friends? There is so much crime. Why does it have to be this way?'"

A $5,000 reward has been offered for information that leads to an arrest. Anyone with information is asked to call the HPD Homicide Division at 713-308-3600 or Crime Stoppers at 713-222-TIPS.