Dan Martino didn't notice anything strange about his neighbor Patricia Diacson's demeanor when he spoke to her at the grocery store where she worked last week.
"Same thing as always," Martino said. "'Hey Dan.' 'Hey Trish.' We see each other. It was very pleasant."
Only hours later, Diacson would murder her grandfather, 80-year-old Robert Girard, according to investigators. Officials say she stabbed Girard 41 times inside their Port Richmond home on the 2500 block of East Lehigh Avenue around 9 p.m. Wednesday.
"To learn about this is horrific," Martino said. "Shocking."
Girard was later found dead and naked on the kitchen floor of the house. Blood covered the first and second floors of the home.
"It just sent a chill down my spine because to be honest, she was the last person I would have suspected," Martino said.
Martino told NBC10 detectives used neighborhood surveillance cameras to identify Diacson as the suspect. She was the last person seen walking into the home before the stabbing.
Diacson turned herself in Monday and was charged in her grandfather's murder, according to officials. Police have not yet revealed a possible motive. Martino said he never heard any arguments or complaints between the two since living next to them.
A friend of Diacson's, who did not want to be identified, told NBC10 she always remembered how much she smiled and how much time she spent with her family.
"It's sad. It really is," the friend said. "She was a good person. I'd never seen her do anything like this."