CLEMENTON, N.J. (WPVI) -- Camden County officials are investigating how a missing former U.S. Marine ended up dead in a lake. No one had seen or heard from him since he disappeared six weeks ago.It was back on the night of Dec. 2, 2016, that 29-year-old Lance James of Clementon, New Jersey, went missing.Area search and rescue teams, including Burlington County K-9 Search & Rescue, had been scouring the area, looking for him to no avail. But they weren't going to give up."We try to be very persistent when we get involved in a case, and we don't wanna stop until it's done," said Thomas Yohanson, Burlington County K-9 Search & Rescue.Family members say James served two tours of duty in the Middle East and when he returned, he suffered symptoms of post-traumatic stress disorder.On the night of Dec. 2, authorities say he had gotten into a fight at the Hide-A-Way Tavern in Clementon, got kicked out and started walking home. Surveillance cameras showed him approaching his apartment a few block away, but then he disappeared. Search teams scored area bodies of water, including Bottom Lake."At that time, there was some ice on the lake and on the other bodies of water that were around, which kind of limited our availability to the waters," said Yohanson.They went back on Saturday, under snowy conditions, with the help of 15 U.S. Marines, but still nothing. But then came the warmer weather we've had the last couple days, and they decided to go back to Bottom Lake - this time the ice had melted."We deployed our Marine unit, and several moments after that, we were able to make the discovery," said Yohanson."It's being able to bring closure to that family, so they can go to sleep at night," he added.The search was fueled that much more by the fact James had served overseas. The circumstances leading to his death remain unknown. An autopsy is to be conducted Saturday morning.