Tbilisi, Georgia ? A man arrested after a fatal shootout with police admitted in video footage shown Thursday to throwing a grenade during a May rally where President Bush was making a speech.

Vladimir Arutyunian’s alleged confession came as investigators found grenades and unspecified chemicals in his home on the outskirts of Tbilisi and tried to piece together his motivations in the incident that cast a shadow over a visit meant to showcase Georgia’s progress.

“I threw the grenade during Bush’s speech,” Arutyunian said from a hospital room, where he was being treated for wounds suffered during a shootout as police tried to arrest him late Wednesday.

One policeman was killed, and the suspect fled into the nearby woods. He was captured about an hour later.

Other video footage released Thursday by Georgian authorities showed Arutyunian lying on a gurney being wheeled from the scene, one of his cheeks swollen and bloody. He made an obscene gesture at the camera.

Bush and Georgian President Mikhail Saakashvili were on the podium in front of a massive crowd in downtown Tbilisi when the live grenade was thrown. The grenade landed less than 100 feet from the podium but did not explode.

A preliminary investigation indicated the grenade’s activation device deployed too slowly to detonate, the FBI said.

Authorities have not commented on whether Arutyunian was connected to any separatist groups in Georgia’s breakaway region of Abkhazia or nearby Chechnya.

The U.S. Embassy in Georgia said Thursday it “welcomes the news that the Georgian Ministry of Internal Affairs, through joint efforts with the Federal Bureau of Investigation, diligent detective work and a strong commitment to solving this case, have taken into custody a suspect.”

The embassy declined to comment on whether the FBI was involved in the arrest or follow-up.