Greek police have brought five people in for questioning in the case of murdered UC Berkeley professor Przemyslaw Jeziorski, who was shot dead on July 4 while visiting Athens to see his children and attend a family custody hearing.

One of the five individuals is the professor’s ex-wife, Greek police spokesperson Konstantina Dimoglidou told CNN.

“Five people have been taken in for questioning, two Greeks and three non-Greek nationals,” the police spokesperson said. “We are waiting to see if arrest warrants will be issued.”

Jeziorski, 43, an economist and professor of marketing at UC Berkeley’s Haas School of Business, was shot multiple times at close range in a residential suburb of Athens and died at the scene, according to police.

A masked gunman “approached the victim on foot and opened fire from close range” at about 4:15 p.m., hitting the victim in the neck and chest, according to police spokesperson Konstantina Dimoglidou. Seven bullet casings from a 9mm caliber firearm were found at the scene, police said.