AUSTIN -- After a 200-mile journey down Interstate 35, escorted by about 200 vehicles, former Navy SEAL sniper Chris Kyle was buried in the state cemetery Tuesday, joining some of the most distinguished names in Texas history.Kyle, considered to be the deadliest sharpshooter in U.S. military history, was killed along with a friend Feb. 2 at a Glen Rose resort's gun range.The procession escorting the white hearse from Kyle's hometown of Midlothian to Austin briefly halted just north of Austin when three motorcycles went down, sending two people to the hospital with non-life-threatening injuries, said Belton police Sgt. Larry Berg. Navy SEALs in the procession rendered first aid until paramedics arrived."Heroes on duty and heroes off duty, certainly," Berg said.Larry Key of Denton, one of about 100 Patriot Guard Riders, said he came to pay tribute to Kyle's service."It's our way of honoring Chris and his family," said Key, a Vietnam veteran.Kyle, 37, completed four tours in Iraq and wrote the bestselling book American Sniper.In Austin, crowds gathered on roads stretching nearly a mile from the cemetery.Mike Lamb, 24, stood about a half-mile from the cemetery wearing a mustard-yellow Marine Corps shirt and holding a sign that read, "Fair Winds and Calm Seas Frogman! R.I.P."An Iraq War vet, Eddie Ray Routh, 25, is accused of killing Kyle and Chad Littlefield. Routh's brother-in-law told authorities that Routh had been diagnosed with PTSD.Monday, about 7,000 people attended a memorial service for Kyle at Cowboys Stadium. Littlefield's funeral was Friday in Midlothian.