A Chicago man stabbed his mother to death then doused her body in chemicals after she refused to buy him tickets to an Avril Lavigne concert, a jury found.

Robert Lyons, 39, was found guilty of first-degree murder Wednesday after a weeklong trial, the Chicago Tribune reported.

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Prosecutors said that Lyons began to argue with his mother, Linda Bolek, when she refused to call a friend to arrange tickets for the concert in 2008.

Lyons stabbed his mother nine times in the back, then poured insecticide and drain cleaner on her body, prosecutors said.

A jury deliberated for just two hours before returning their verdict, the report said.