Earlier this week we told you about the murder of Florida State University professor Dan Markel. Now Matt Gutman of ABC News provides an update.

Grim Details Emerge in FSU Professor’s Shooting Death

A criminal law professor at Florida State University gunned down at his home was shot in the side of the head at relatively close range, ABC News has exclusively learned.

Professor Dan Markel, 41, was fatally shot Saturday in the Betton Hills section of Tallassee, Florida, a neighborhood marked by Spanish moss and ranch-style homes.

Investigators believe Markel knew his killer and may have literally opened his door to his own death.

“He was the intended target in this situation,” Tallahassee Police Department Officer David Northway said.

Police have released pixelated pictures of a silver Toyota Prius which they say was seen in the area on the day of the crime. A police tip line has netted 50 calls so far.

One potentially big clue is that there was no sign of forced entry into the house.

“There’s not enough information to suggest that this is a contract murder. It certainly could be,” said ABC News consultant Brad Garrett, a former FBI agent. “The most likely theory is that it it’s somebody that he knows.”

With no suspects named, police are being careful not to reveal certain evidence.

“We must make sure that we are keeping the integrity of this case so we can bring it to prosecution,” Northway said.

Markel’s death has rattled the college town. The Harvard grad had been published in the New York Times and served as a legal scholar, with a focus on criminal law.