01/23/2014 02:45 pm ET Updated Jan 27, 2014

Al Filan, Longtime Brother Rice High School Teacher Stabbed To Death By Prostitute: Police

Updated story

A popular and long-serving teacher at an all-boys Catholic school in Chicago who was found stabbed to death in his suburban home Tuesday was killed by a prostitute, police say.

Police arrested Alisha M. Walker, 20, of Akron, Ohio on Friday in connection to Filan's death. Police, who tracked the woman to Fort Wayne, Ind., said she met Filan through an internet classifieds site and killed the 62-year-old over a dispute about money, DNAinfo Chicago reports.

Walker's family says the woman acted in self-defense after her friend -- who was allegedly also at Filan's home at the time of the incident -- was threatened. "There's a lot more to the story," Ed Hensley, Walker's Kentucky-based uncle told the Tribune. "I don't know all the details but I believe her."

Al Filan taught at Brother Rice in Chicago's Mount Greenwood neighborhood for 39 years, teaching business, chairing the business department and coaching soccer, according to DNAinfo.

Filan had barely missed a day of work in his nearly 40 years as a teacher, the Tribune reports. Police making a well-being check after Filan didn't show for work found him unresponsive in his suburban Orland Park home Tuesday morning.

The medical examiner ruled Filan's death a homicide. An autopsy revealed he died of ''multiple stab and incise wounds,'' ABC Chicago reports.

“He was a leader on the staff. He was a mainstay. He was admired, respected. He was a mentor to many of our younger staff members. They looked up to him. He was a beloved faculty member,” Brother Rice President Dr. Kevin Burns told CBS Chicago.

“Always went the extra mile for his students," Burns added. "There’s no question this is a huge loss for everyone at Brother Rice."

"This school's really going to miss him, his upbeat personality and all that," Brother Rice sophomore Zack Meegan told DNAinfo. "He was a really good teacher. He was a very good supervisor and mentor."