A Hudson, FL, man believed to have shot and killed his mother's friend and then exchanged gunfire with deputies is dead, the Pasco County (FL) Sheriff’s Office has confirmed.

The sheriff’s office said the suspect was identified as Brian DeCerio, 30. He reportedly was known to have guns and had a history of mental illness, reports WFLA.

Deputies said DeCerio believed that his mother’s friend was trying to hit on his girlfriend. Sheriff Chris Nocco said DeCerio did not a have a girlfriend, but in his mind he did.

The suspect reportedly shot and killed the victim with a long gun.

Deputies arrived and exchanged gunfire with DeCerio, engaging in a gun fight in the middle of the street within a block of a school.

DeCerio eventually went into his home and deputies followed, where they found the victim. DeCerio was later found dead inside the home.