There were 5 suspects. Who killed her ?

A woman was brutally murdered at noon on Christmas.
There were 5 suspects.
They were all questioned about their whereabouts of that that day.
These were their statements;

Suspect #1 : I was with my wife that day. She gave birth to our son so I was at the hospital with her.

Suspect #2 : I don't remember exactly what I was doing but I can sure as hell tell ya I wasn't killin nobody.

Suspect #3 : I was shopping at the mall for late Christmas presents.

Suspect #4 : I don't have to answer this.

Suspect #5 : I was walking my dog around the park. Same as every other day at noon.

Who killed her?