Robert Lyons, 39, got into a heated argument with his mother over Avril Lavigne concert tickets in 2008. Lyons was so angry at his mother, 61-year-old Linda Bolek, that he murdered her.
Bolek's body was discovered in the condo that she shared with Lyons in Carol Stream, Illinois. She had been stabbed nine times.
What exactly was the Avril Lavigne-spurred argument about? Apparently, Lyons was upset that his mother refused to call a friend to arrange for tickets to an Avril Lavigne concert that Lyons wanted to attend, reports the Chicago Tribune.
Lyons was found guilty of first-degree murder on Wednesday.
The jury also found that Lyons' crime was particularly brutal and heinous. This finding makes Lyons eligible for life behind bars.
Lyons' public defender did not dispute the murder. During the trial, the defense argued that Lyons should be convicted of the lesser offense of second-degree murder.
The difference between a first-degree and second-degree murder charge is that first-degree murder usually requires premeditation.
This generally means that the killer must have thought about the killing or planned it out.
Lyons' defense likely argued that he killed his mother in the heat of the argument.
The prosecution, however, argued that Lyons had been planning to kill his mother for some time, according to the Chicago Tribune. Planning to kill someone amounts to premeditation, and to first-degree murder.
The jury sided with the prosecution. Robert Lyons will likely face many years behind bars - all because of an argument spurred by Avril Lavigne concert tickets. He is set to be sentenced in November.