Updated

As a new American resident, Gelareh Bagherzadeh frequently embraced her freedom to speak critically about human rights policies in her native Iran, but friends and family members said they never knew her peaceful activism to attract any enemies.

That's why, like investigators, they've been at a loss for answers since Bagherzadeh was found shot to death last weekend in her car. The motor was still running and her wallet and cellphone were still by her side after the vehicle crashed into a garage door in the upscale Houston townhome complex where she and her parents lived.

"There are people that believe any outspokenness can be risky behavior. That's not my opinion here," said Fiona Lonsdale, who knew Bagherzadeh from a Persian Christian group at their Baptist church in Houston. "I think it's more of an act of violence that no one can explain."

The fatal shooting remains surrounded by mystery in part because nothing was taken from the vehicle, though authorities haven't ruled out the possibility it could have been a botched robbery. They also haven't found any evidence suggesting she was targeted for her nationality or activism.

Ali Bagherzadeh, her younger brother, said he doesn't know why anybody would have wanted to harm his sister, who 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.

"I can't think of any enemy, anybody that would hurt her, because she has always been peaceful and just tried to bring peace to this community and this society," he said Wednesday at a Crime Stoppers news conference.

The 30-year-old was active with SabzHouston, a Houston-based group formed to protest the current Iranian government after its contentious 2009 elections. She was an outspoken supporter of women's rights in her home country and had recently converted from Islam to Christianity.

"She once told me that her rights counted for nothing in Iran," Lonsdale said. "But now in the U.S., she was going to speak for every cause she believed in."

Lonsdale and several other friends said they didn't believe Bagherzadeh's activism was connected with her death.

Luke Kohanloo, who also knew Bagherzadeh from their church group, said he remembers his friend as always smiling and joking. He called her "a real fighter."

"She was a strong Persian woman who would stand up for her rights. She never gave up her right to speak, to demand freedom for our nation (Iran)," Kohanloo said Wednesday evening during a memorial service.

Bagherzadeh's family members could not be reached for comment Thursday as several listings were not valid. Friends told The Associated Press the family was not speaking publicly beyond her brother's brief statement.

Bagherzadeh had been driving in her townhome's complex near Houston's upscale Galleria area around 11:40 p.m. Sunday when someone shot her from outside her car, hitting her head. Capt. David Gott, with the Houston police homicide unit, said investigators believe she was on her way to her townhome when she was shot.

Her body was found slumped behind the wheel after the vehicle crashed into the garage door, the tires still spinning.

While there were no known witnesses to the shooting, Bagherzadeh had been on her cellphone talking with an ex-boyfriend, who authorities said heard a loud thud and a screeching noise but no gunshots. After interviewing him, they determined he is not a person of interest.

Surveillance video from one of the townhomes where the shooting took place was reviewed but provided nothing useful, police said.

Police also looked into a 2010 assault report that Bagherzadeh filed against a male acquaintance. She did not file charges, and police declined to identify the acquaintance. They said he also isn't suspected in connection with her death.

Gott said some physical evidence from the crime scene was being tested in the Houston police crime lab, but he declined to say what it was. Authorities and the family were also hoping a $5,000 Crime Stoppers reward would spark new leads in the investigation.

"We're still asking the public to come forward," Gott said. "Somebody is bound to know the people that committed this offense. Come forward and let us know."