He was with two other people in the neighborhood because he reportedly wanted to borrow a bicycle from a buddy. According to the prosecution, this is what drove Mercer to the crime scene—he was attempting to shoot Wayne when he killed Rhys.
But defense attorney William McCuaig says otherwise. He claims that the gun went off by accident while Mercer was trying to show it to someone outside Wayne's house - not as part of any plan to kill him.
"There was no intent to shoot Wayne," McCuaig said during one court hearing. "The gun went off by mistake."
McCuaig also says that there was a third person in the car with Mercer and Wayne - a woman who is now charged with accessory after the fact. She's being tried separately.
Prosecutors say that they believe Mercer shot Wayne intentionally because he has previously admitted to police that he hates gay people. But they say that they can't prove it beyond a reasonable doubt - which means that it could come down to a jury deciding whether or not to believe Mercer's claim that he accidentally fired the gun.
In addition, prosecutors say that they want jurors to consider the fact that Mercer had been drinking before the shooting - but McCuaig argues that his client wasn't drunk enough to be convicted of murder.
Mercer, Sean Sean Mercer Mercer was sentenced to at least 22 years in jail after shooting and killing Rhys on August 22, 2007. During the trial it was revealed that prior to the incident, Mercer had been involved in a fight with another man over a girl. When asked why he had gone through with the murder, Mercer said that he had done it because he was "in a hurry". He also added that he did not think that he would get caught because "no one knows I was there."
After hearing this explanation, jurors returned a verdict of guilty on both counts. Sean's lawyer claimed that his client was mentally ill at the time of the crime and should be sent to a hospital instead of prison. However, prosecutors argued that there was no evidence that Sean was sick or in need of medical care. They also said that he had shown no signs of illness during the trial and seemed perfectly sane.
In addition to being charged with homicide, Mercer was also convicted of aggravated burglary for breaking into Rhys' house. This crime is usually punished by up to 10 years in prison, but due to the nature of the offense, prosecutors were able to ask for 20 years behind bars. The judge agreed to give him the maximum sentence for both crimes.
Taylor's boyfriend, 27-year-old Kenneth Walker, shot him in the leg as police entered the residence, according to Mattingly, and Walker then started fire. The officers fired 32 rounds, killing Taylor and injuring eight others. Officials decided Mattingly was shot by Walker, according to Kentucky Attorney General Daniel Cameron.
Walker had a history of violence against women. He was arrested in 2001 for wanton endangerment after he pointed a gun at his girlfriend's head and threatened to kill her. In 2003, he served five months in jail after being convicted of domestic violence assault against his wife.
Mattingly had been dating Taylor since late 2007. They lived together in a house that Mattingly bought for $30,000 in March 2008. Mattingly was employed as an assistant manager at a Wal-Mart store in West Palm Beach until he was terminated in February 2009. He was also charged with possession of cocaine during this time.
Walker filed for divorce from his wife in April 2009, just over a month before the shooting. The case is still pending.
Mattingly has been charged with seven counts of felony murder and one count of attempted first-degree arson. If convicted on all charges, he could face the death penalty. His attorney says he will plead not guilty by reason of insanity.