MADISON, Wis. -- Joel Marino's parents said they have mixed emotions about the apparent suicide of Adam Peterson, the man convicted of killing their son last year.

READ: Authorities: Man Convicted In Marino Slaying Commits Suicide In Prison | VIDEO: Watch The Report

Lou and Debbie Marino on Sunday night said that they're glad it's done, but no matter what happened, nothing was going to bring back what Peterson took away from them.

"It's a relief the thing's done," said the Marinos. "Then, of course, it always brings back more heavily that Joel's gone, you know, forever."

Lou Marino said he learned of Peterson's death at a prison in Waupun late Sunday afternoon. Authorities said that Peterson apparently hanged himself in his cell.

Lou Marino said the first thing he did was sit down and cry -- not because Peterson was dead, but because the book was finally closed.

Marino said he's still grasping how he feels about the death and if justice was indeed served, but for now, he said a huge weight has been lifted off his shoulders.

Since Peterson's guilty plea last month, Marino said he had been preparing for the sentencing, gathering notes and stories to convince the judge that the stiffest penalty was necessary.

"Everything is running through your mind, a lot of emotions, a lot of positive thoughts, good remembrances of Joel," said Marino. "But eventually this whole process comes back to.'It's never going to bring Joel back, he's gone.' But it's nice the legal stuff is done."

The Marinos said they can't thank enough family, friends and even complete strangers who have offered support to them during what was a very difficult year, WISC-TV reported.

They also said that even though they didn’t' always see eye-to-eye, they wanted to thank Madison police and Capt. Jim Wheeler for their work on the case.

The Marinos now say they'll work on the next step which is moving on -- trying to forget what happened -- but never forgetting their son, Joel.

Stay tuned to WISC-TV and Channel 3000 for continuing coverage.