Greek authorities said the ex-wife of a slain California college professor and four other people were brought in for questioning Wednesday, weeks after the victim was gunned down outside the Athens home of his former spouse.

A Greek police spokeswoman told CNN that those being questioned in the killing of Przemyslaw Jeziorski, 43, include “two Greeks and three non-Greek nationals. We are waiting to see if arrest warrants will be issued.”

The brother of Mr. Jeziorski, who taught at University of California, Berkeley, said police told him the ex-wife’s current lover shot the victim five times on July 4 as he was going to see his twin children.

The couple were locked in a custody battle at the time of his slaying, according to KGO-TV.

Police officials told CNN previously that the deadly shooting “bore the signs of a contract killing,” and that close family members were also being investigated in the murder probe.

Relatives said Mr. Jeziorski, a Polish native, was in Greece to attend a child custody hearing.

He had gone to court the day before police said a masked gunman walked up to him and opened fire at point-blank range.

“I never thought something like this would happen to my family,” Lukasz Jeziorski, the victim’s younger brother, posted on Facebook. “My brother went to meet his beloved children — Zoe and Angelo. He was murdered in cold blood on the road near the house where his children live.”

UC Berkeley also mourned the professor’s death by posting a lengthy profile Monday about his 13-year tenure with the school.

Mr. Jeziorski joined the college’s Haas School of Business in 2012 and became a leading researcher in marketing and economics.

“I am heartbroken by news of the tragic and sudden death of Professor Przemyslaw Jeziorski, a beloved member of our marketing faculty and Haas community,” Dean Jenny Chatman said in a release. “Our focus is on supporting our community during this difficult period. My heart goes out to Przemek’s family and loved ones. We will miss him.”

• Matt Delaney can be reached at mdelaney@washingtontimes.com.