"(Kyle) was the last person that I would have expected to end up like that," Lamb said. "Because he was so into Wounded Warriors and helping soldiers with (post-traumatic stress disorder). He was a warrior overseas and at home."
An Iraq War veteran, Eddie Ray Routh, 25, has been charged in the killings of Kyle and his friend Chad Littlefield. Routh's brother-in-law told authorities that Routh had recently been diagnosed with PTSD.
Authorities say Kyle, Littlefield and Routh arrived together at the Rough Creek Lodge shooting range, about 50 miles southwest of Fort Worth, on the afternoon of Feb. 2. Routh later fled in Kyle's truck.
According to a search warrant, Routh told his sister and brother-in-law that the men "were out shooting target practice and he couldn't trust them so he killed them before they could kill him."
On Monday, some 7,000 people attended a two-hour memorial service for Kyle at Cowboys Stadium in Arlington. Kyle's coffin was placed at the Dallas Cowboys' star at midfield.
His widow, Taya Kyle, told the crowd she was broken but that her family would "put one foot in front of the other" to get through their grief. She said she told her two children that they will remember Kyle's silly side, Texas twang and the prayers they prayed together.
Littlefield's funeral was held Friday in Midlothian. Afterward, Littlefield's relatives said the outing with Routh was intended to be therapeutic.
Stengle reported from Midlothian. Associated Press writer Angela K. Brown in Arlington also contributed to this report.