TALLAHASSEE, Fla. -- Detectives in Florida say Canadian law professor Daniel Markel was shot in the head, but won't say whether he was shot from the front or back. They say he was gunned down at his home in broad daylight, but won't say if he was found inside the house or outside. They released a photo of a vehicle of interest, but wouldn't confirm exactly where the car was seen or even the make and model.

But they have made one detail perfectly clear: Whoever did it wanted Markel dead.

Last Friday's shooting of the popular lawyer has stunned friends, colleagues and residents of his well-to-do community in Florida's state capital, who demanded to know whether Markel had surprised an armed burglar or robber. No, Police Chief Michael DeLeo said -- this was a premeditated murder.

Tallahassee police spokesman David Northway released photos of a vehicle of interest Wednesday and asked for anyone with surveillance in the area to contact police. The car appears to be a silver or light green Toyota Prius, though police will not confirm that.

CrimeStoppers has increased a reward for information leading to an arrest from $1,000 to $3,000.

Markel, 41, was born in Toronto, where a funeral was held Thursday at Benjamin's Park Memorial Chapel. His family has asked for donations to go to the Crohn's and Colitis Foundation of Canada, Canadian Magen David Adom, the Shomrei Torah Synagogue or Harvard Hillel.

Markel was the father of two boys and a 2001 graduate of Harvard Law School. He practised white-collar criminal defence and civil litigation before joining the Florida State law school as a faculty member in 2005. He was tenured in 2010.

Bob Jarvis, a Nova Southeastern University law professor, said there are numerous reasons police withhold crime details from the public, even when seeking tips. Prosecutors worry about affecting the jury pool, and police are always concerned with false confessions and copycat criminals, he said.

"It's a way to test anybody who's either making a confession, who's trying to pin the blame on somebody else," Jarvis said. "It's a truth-telling test.

"You don't want confusion. If there's something unique about the killer or the killer's M.O., you'd like to keep that under wraps."

Markel finalized a contentious divorce from his ex-wife, Wendi Adelson, in 2013. The two had equally split custody of sons Benjamin and Lincoln, but they had follow-up litigation over money settlements. At one point, Adelson, who also teaches law at Florida State, hoped to move back to her hometown in South Florida.

"She's a basket case, she's totally, totally shocked over what happened," said Adelson's lawyer, Jimmy Judkins. "Gone from having children with two parents to children with one parent with no warning.

"She's scared to death for her children. She's scared to death for herself."

Judkins said Adelson has co-operated with police and has not been asked remain in the area.

Tamara Demko met Markel at Harvard Law School, and the two had been friends ever since. She saw him regularly in Tallahassee and created a web page for the Dan Markel Memorial fund to raise money for his sons. The site collected more than $18,000 in the first day.

Demko sobbed as she remembered the way he gave everyone nicknames and how he doted on his sons. She described his love for academia and said he was devoted to his Jewish faith.

"My heart is just shattered," Demko said. "I just don't know what I'm going to do without him in my life. He's been a part of it for so long."

Demko said Markel took joy in life and his friends.

"He loved sharing his life with all the people that he met along the way."

David Wilkins has been a Harvard Law School professor since 1986 and remained in contact with Markel over the years. Markel's death has been an ongoing topic in the law community -- where he was well-known among other scholars for his writings in blogs and scholarly publications, several focused on crime and punishment.

"He loved people as much as he loved ideas," Wilkins said. "He loved talking about ideas to people. I think that's what drew a lot of people to him."