Diaz allegedly mortally wounded a man in his 60s, whose roommate found him with stab wounds to his chest in their home and notified police shortly before 7 p.m. Monday, police said. The injured man was transported to a hospital, where he died. His name wasn't publicly available as of Thursday afternoon, according to the Santa Clara County Medical Examiner-Coroner's Office.
At about 9 p.m. Monday, as police were investigating the stabbing death, an officer was approached by another man who reported he had just been punched and knocked down by a person, later identified as Diaz, while walking through the mobile home park, police said. The man's mouth was moderately injured, and he was treated at a hospital.
Officers found Diaz in his home and arrested him without incident for the battery, police said.
Detectives and crime-scene investigators later connected Diaz to the stabbing and arrested him on a warrant while he remained booked in Santa Clara County Main Jail in San Jose around 4:30 a.m. Thursday, police said.
Diaz has been living with his grandmother in one of the park's cabin units for the past two years, said Rosemary, whose last name is being withheld to protect her privacy. He's been her caretaker and aide and has never been violent, she said. The charges against him came as a complete surprise.
On Monday evening, Diaz had been hanging out with friends in Buena Vista. Rosemary said she told him she was going to get antifreeze for her car and was gone for about 1 1/2 hours. When she returned, she made dinner while he was outside.
Rosemary had gone to bed when the police knocked on her door. She said she heard them tell Diaz, who was in the home, "We heard you did this," referring to the alleged punching. Police told her not to let him out of the residence while they investigated. But Diaz did leave the home, and when he returned, police arrested him for the assault, she said.
"They say he was under the influence of drugs. I don't even know what to look for in a person to tell what that's like," she said.
Diaz previously lived in Stockton and in Merced and had an episode of homelessness before moving in with her, Rosemary said.
Diaz had some scrapes with the law in the past, although she said family never discussed the circumstances with her. He was not on parole as far as she knew, and he had turned his life around.
"He really wanted to get into a church," she said, noting that he joined one on Middlefield Road.
"He would help feed the homeless. The church even gave him a part-time job. He would get up early and set up the table and chairs, and on Sundays he would set up for brunch. He would make peanut butter and jelly sandwiches and gave them to the homeless on buses. Every time he would see someone in need, he gave them money. He was very caring."
But he also had nagging medical issues stemming from a gunshot wound to his head several years ago.
Rosemary said police took one of her cars, which Diaz drove, to look for evidence. They also confiscated her trash.
As news broke of Diaz's arrest for the homicide, residents said they were surprised by Diaz's alleged actions and that anyone would kill the man in his 60s. Both were friendly to their neighbors and both were generally quiet.
"We never saw any problems from both of them," Pedro Landarellano said.
"Knowing (Diaz) lived here, it's kind of scary. You don't know what else someone would do. It makes you think who else would do something like that. We just used to see him outside drinking a beer," Melanie Garcia said.
Both Landarellano and Garcia said that they suspected Diaz may have been involved in the stabbing after his arrest for the assault.
"It all happened on the same day. It's an easy connection to make," Garcia said.
Alan Cochran, the resident who was allegedly assaulted by Diaz, said the beating was "totally unprovoked."
Cochran was talking to a group of people when Diaz suddenly emerged from his home and approached Cochran. The two had never met, he said.
"I was standing in front of a unit and he hits me so hard that I fell to the ground. Then he kicked me," Cochran said. "I don't even remember. An eyewitness saw him, and then he went back to (his unit)."
'He had an adventurous life'
Buena Vista residents this week reacted with shock at the homicide. People living nearest to the victim's trailer said they hadn't heard any noise or altercations before his body was found.
Buena Vista resident Jennifer Havens, who lives with her son, said she'd known the victim for over 10 years and called him a friend. He was "really ornery when I first met him, but he has a good heart. We had kind of a love-hate relationship," Havens said.
She gave him a stray cat named Ebony, with whom he developed a close relationship. However, he had to put down the cat on Sunday because the animal had cancer.
Multiple residents said the man was a good person who was distraught over losing his cat. One neighbor who lives a few spaces away had given a photograph of the cat to the man on Sunday.
Two men in their 20s who also live down the lane said they were saddened by the man's death. The mobile home park is a place where people help each other and accept each other's quirks and differences, they said, adding they've never felt unsafe in the community.
"He was a good person. He never disrespected anyone. He never attacked," said one young man, adding that he was well-known in the park.
The two were among the neighbors who would visit with the man in his trailer. He would regale them with stories about his adventures in the 1960s and 1970s.
"He went to Woodstock. I think he had kind of an adventurous life when he was younger. He really liked sports. He had a collection of baseball caps. He used to have barbecues. One thing he liked a lot were Hawaiian shirts. He would wear them every day," one young man said.
He shook his head. "I've known him practically my whole life. Every day I would walk to the store and pass his trailer," he said.
The man had siblings, but they never saw them visit.
"He was really lonely," the young man said.
The second young man used to bring over auto parts for the deceased man's Oldsmobile Cutlass Supreme.
"He was a good guy. He was relaxed. We would talk sometimes and share a beer," he said. "He never had problems with anybody that I knew of."
The neighbor who gave the photograph said the man did have friends who frequently came to the home, usually by bicycle from other parts of the Bay Area and Palo Alto.
"He was in contact with his mom, and she provided for him to live on his own," the neighbor said.
Neighbors thought there would likely be some sort of memorial at Buena Vista for the victim.
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