A hulking madman was caught on tape viciously stabbing an elderly couple in their Queens apartment building, then calmly straightening the bent and bloody knife.
David Williams, 41, drove a carving knife into John Purcell and his wife, Joan, as the loving couple left their Northern Blvd. building in Flushing, cops said. A third victim, 41-year-old Juhn Fook, was also stabbed
"Blood everywhere," an officer said.
A motion-activated security surveillance camera captured the horror.
At 9:12 a.m., Williams is seen punching Deraj Maraj, 37, for no reason
. "He just walked up and started swinging," Maraj said later. "He looked like he was crazy."
Eight minutes later, at 9:20a.m., the video shows canvassing officers and Maraj entering 147-15 Northern Blvd.
At 9:31 a.m., cops leave the building. Seven minutes later, Joan and John Purcell leave the building, holding hands.
At 9:39 a.m., Williams enters the frame. In the span of a minute, the video captures Williams pointing the knife at the couple, the Purcells walking toward the street - where they eventually collapsed - and Williams straightening the knife against a railing
The couple and Fook were taken to New York Hospital Medical Center of Queens. Joan Purcell, 71, underwent surgery and was clinging to life while her 78-year-old husband and Fook were in serious condition.
Maraj told cops Williams may have ducked into the Purcells' building after punching him. Officers searched the building and another one nearby, but didn't find Williams.
The NYPD believes Williams slipped into his building, at 147-25 Northern Blvd. Cops later took the 300-pound Williams - who was still gripping the bloody knife
- into custody.
Williams, who works as a bouncer at Submarine karaoke bar in Flushing, also has two arrests in the last five years for molesting kids
Those who know Williams, whose behavior seemed erratic at times, had mixed feelings about the local man who was raised by his religious mother.
"There will be days when he has this weird look on his face," said Michael, a close friend of Williams' who asked that his last name not be used.