State police analyzed blood found in Howell's van and determined it belonged to Arizmendi.
Blood belonging to another person was also found in the van. However, investigators have been unable to figure out to whom it belongs.At the time of the victim's disappearance in 2003, Howell had been in Connecticut doing odd jobs like mowing grass at homes and businesses in Hartford, Wethersfield, West Hartford and New Britain.
In addition to the unidentified blood, the state police Cold Case Unit said it is trying to identify two women who were seen on video recovered from inside Howell's van.
There were six video tapes found in the van, and police said they were of Howell, with unknown women, engaging in sexual acts. Arizmendi was not on the tapes.
A video recorder and equipment were also found in the van.
Police said Howell has a lengthy criminal history along the east coast, including burglary, and he has shown violence against women.
A previous girlfriend of Howell's said he ripped the telephone from the wall once to prevent her from calling police, restraining her from running away from him, and punched her in the left eye, the back of the head, and in the stomach.
Howell is not eligible for parole until February 2018.
More information about Howell's manslaughter case can be found on the DCJ's website here.
People in Howell's old neighborhood said they remember seeing him with his girlfriend, identified as 48-year-old Dorothy Holcomb at her home years ago in New Britain.
Neighbors said the house, in New Britain, was knocked down years ago due to asbestos and was replaced with a church parking lot.
"They weren't friendly, I never had a conversation with them," said neighbor Anna McBride.
Details about how Howell has been connected to the seven bodies found in New Britain have not been released.