PALMDALE, Calif. (KABC) -- A man was shot and killed by a security guard after crashing his car into a restaurant, stripping off his clothes and stabbing someone at a McDonald's in Palmdale, police and witnesses said.The bizarre incident unfolded Sunday at a shopping area in the 2500 block of East Avenue S. around 4:30 p.m.Officials say the suspect crashed his car into a Carl's Jr., then got out of the vehicle and stripped off his clothes.He ran across the street to a McDonald's and there stabbed at least one person inside.He then got into a confrontation with a security guard, who shot the man, officials say."Security approached him and he tried to stab the security officer and the security officer defended himself by firing his service weapon," said Juan Paiz, the owner of the private security company.Witnesses say they heard several shots."All I hear was pop pop pop," said one witness. "So I ran over here, I see this guy on the ground."The suspect later died at a hospital.Investigators are still looking at what could have driven the man to this behavior. It was unknown at this time if any controlled substances were involved.The man who was stabbed at McDonald's, believed to be about 88 years old, was described as in stable condition.