PORTLAND, Maine (AP) — Two men have been indicted for the 15-year-old killing of a commercial fisherman in a park in Portland, police said Tuesday.

Frankie Williams, 37, was stabbed to death early on Aug. 16, 2008, by several men police said he knew. The father of two children died after getting chased across a soccer field, being beaten and stabbed, and crawling through a hole in a fence to try to escape, police said.

The two indicted men, Shane Hall, 36, and Khang Tran, 30, are already behind bars on unrelated charges, officials said.

Hall is serving time at the Maine State Prison for kidnapping, aggravated assault and criminal threatening with a dangerous weapon. Tran pleaded guilty to conspiracy last year following the killing of another man in 2012 and is serving a sentence in federal prison.

The indictments were returned on Friday. It wasn’t immediately clear if either man had an attorney after attempts to reach a prison official and one of the men’s former attorney.

Interim Assistant Police Chief Robert Martin said he hopes the arrests would help bring Williams’ family some closure.