Arlinksy was a forensic anthropologist.
Arlinksy traveled to the Yukon Territory with Babcock to see the apparent body of an Extraterrestrial biological entity found by a Canadian team. Traveling by helicopter, they met Rolston, a guide, and reached the site and took pictures and ice core samples. Arlinksy then contacted Fox Mulder to ensure that the authentication would occur without unknown parties disrupting it, as he was absolutely certain the body was genuine. After showing him the pictures and giving Dana Scully the ice core sample for further study, he traveled with Mulder back to the site to show him in person.
However, when Arlinksy and Mulder reached the helicopter landing pad, they found no one. On the way to the site, the found Rolston dead and indeed the whole team at the site, all dead by gunshot except for Babcock who was wounded. Babcock said he had hid the body from the attacker after he left. The three of them brought the body back to a Washington, D.C. warehouse to conduct the authentication. Arlinksy seemed to observe a lot of unique details of the body and all of them seemed convinced.
After Mulder got a call and left the warehouse, a man came and, after Babcock revealed he was expecting him, killed Arlinsky. (TXF: "Gethsemane")