A background check of an ex-convict charged with stabbing an Auburn man to death this week led state police Tuesday to another ex-convict sought in the fatal shooting of his father in Maine two years ago.

David Mair had been sought since he disappeared around the time his father’s body was found in woods behind the Fryeburg home they shared. As of Tuesday afternoon, Mair was in jail but still not charged in the death.

“He’s not talking to us, ” said Assistant Attorney General Thomas Goodwin.

Mair, 20, was being held in the Androscoggin County Jail on a robbery charge in a separate incident in Lewiston last week.

State police said Mair insisted his name was David Knox when they and Lewiston police arrested him early Tuesday.

Fingerprint comparisons and tattoos matched Mair’s, however, and his mother verified the identification.

“It was obvious at that point the jig was up regarding his identity, ” Goodwin said. He added that some of the state police detectives working on the Auburn stabbing case also helped investigate the July 22, 1992, slaying of David Mair Sr.

Mair had returned to Maine about a week ago after serving time in a Massachusetts jail for assault, said Goodwin.

Although state police had sought the younger Mair since the shooting, they never knew he was behind bars in Massachusetts because he was using the David Knox alias. Mair was a juvenile when his father was killed, Goodwin said.

It was Mair’s connection to Daniel McLeod, another Massachusetts ex-convict who was charged Monday with murdering Charles Magno of Auburn, that piqued investigators’ interest.

Although McLeod is charged only with murder, state police said he also participated with Mair in beating and robbing a Lewiston man last week.

“They were both involved in that robbery together, ” said state police Detective Sgt. Michael Sperry.

McLeod, 34, was released several months ago from the former Walpole State Prison, now called the Massachusetts Correction Institute at Cedar Junction, where he served nearly three years for armed robbery, Goodwin said. Since then, he has been living in the Lewiston-Auburn area, state police said.

McLeod and Mair did not know one another until they met in Maine, Sperry said.