The investigation focused on two separate locations.
The first scene was on Whistling Swan near Wetstone, where a minivan crashed into a home around 2:15 a.m. Responding officers found the victim dead with apparent stab wounds. He was identified as John Alexander Bash III, 38.
Eyewitness News spoke with a man who said the victim was his brother-in-law.
"My brother-in-law was an amazing person.... He had an accident... multiple years ago. He had a spinal injury and he was confined to a wheelchair for the rest of his life," said Lindsey Myers. "In this situation, he's a defenseless victim, and he just had no chance to defend himself."
Investigators said the suspect, 47-year-old Aaron Matthew Shindle, was Bash's former caregiver.
The second incident happened a short distance away about an hour later. Around 3:25 a.m., Irvine officers contacted Shindle near Stone Creek South and West Yale Loop.
Police said Shindle raised a weapon at officers, which led them to open fire. Shindle was struck and taken to a hospital, where he later died.
Authorities said a knife was recovered at the scene. No officers were injured.