A knifeman who allegedly stabbed a 68-year-old man to death in broad daylight had been released from jail just a day earlier. 4 Marcos Iriarte-Valdez is pictured in a surveillance video capturing the fatal stabbing of a Martinez man. Iriarte-Valdez allegedly killed Todd Stewart outside his home in a terrifying attack caught on video in Martinez, near the Bay Area, California on Thursday. He stayed inside the vehicle for a brief period before exiting and allegedly launching the brutal knife attack on Stewart. 4 Surveillance video captures Iriarte-Valdez appearing to exit a silver vehicle on the residential street.