SACRAMENTO (CBS13) ― The Zodiac Killer murdered several people, terrorizing the Bay Area and taunting police in the 60's and 70's. The FBI confirmed to CBS13 on Thursday that they are now running laboratory tests on some items that may link a suspect to the killer.

The evidence was given to the FBI by a Pollock Pines man who also claims he recently found the disguise worn by the Zodiac Killer during one of his attacks.

"The identity of the Zodiac Killer is Jack Tarrance. He's my stepfather," said Dennis Kaufman.

Eight years of Dennis Kaufman's life has been consumed with attempting to prove the only father he's known since he was five-years-old is none other than the Zodiac Killer.

"This is a handwriting comparison I did," Kaufman said, showing handwriting samples of what he claims to be his stepfather's and the Zodiac Killer's. He claims the samples are too similar to be coincidence.

"The composite is a dead ringer," Kaufman said, showing composite sketch of the killer next to his stepfather's -- a resemblance that is undeniable between pictures of Jack Tarrance and descriptions of the zodiac.

Kaufman also claims his stepfather, in a taped phone conversation, indirectly admitted being the zodiac killer.

Jack Tarrance died in 2006. Kaufman said that while going through Tarrance's belongings, he made some disturbing finds. One piece of evidence he plans to turn over to the FBI is a knife still covered with what could possibly be dried blood.

"It could be a knife he barbecued with or a knife he murdered someone with," Kaufman said.

Jack also left behind rolls of undeveloped film which will also be turned over to the FBI. On the one roll Kaufman did develop, there were gruesome images.

"[It] appeared to be people who were murdered," he explained.

Just recently, Kaufman remembered his stepfather asking him several times about an old PA system, which led him to take it apart.

"When I first opened it up that did affect me. My heart skipped a couple of beats when I saw it," he said.

The material folded and tucked inside, Kaufman believes, may unmask the zodiac killer.

"It was a black hood with a zodiac on it," Kaufman said.

It's similar to the hood worn during the vicious 1968 Lake Berryessa attack, which could be key evidence connecting his stepfather to the killings. He also believes there are dozens of additional victims which were never linked to the Zodiac, including Kaufman's own mother, who he claims was suffocated.

"She sat there and told me Jack was trying to kill her and I didn't listen. I can only imagine how she felt. Imagine how scary that would be. That is what kept me going this whole time," he said.

The FBI confirmed they are running DNA tests on items that Kaufman gave them.

Kaufman said there are letters sent to him by his stepfather, and authorities are trying to get DNA profile of Jack Tarrance to compare to the Zodiac Killer. The FBI told CBS13 they could get those results back any day.