A 14-year-old boy thought to have been killed either by Israeli gunfire or from internal Palestinian violence last week turned up unharmed at his family’s house after trying to sneak into Egypt via smuggler tunnels and being held by Egyptian security officials, his parents said Saturday.

The boy, Muhammad al-Farmawi, disappeared on Tuesday when Palestinian demonstrators clashed with Israeli forces along the Gaza border. It was Land Day, the anniversary of the 1976 protests against Israeli land expropriation in northern Israel in which six Israeli Arab citizens were killed in confrontations with Israeli security forces.

The youth’s father, Zidan al-Farmawi, 42, spent four days at a hospital emergency entrance, looking inside every arriving ambulance for his son.

He was amazed at the boy’s return on Friday, when it was revealed that Muhammad, along with 16 other teenagers, had sneaked into smuggler tunnels to try to get into Egypt and was then picked up by Egyptian security forces.

“It was a very big shock for us,” Mr. Farmawi said. “We were told that he had been killed by Israeli fire and that his body had been left near the fence at Rafah,” in southern Gaza.

In 2002, Muhammad was seriously wounded by a gunshot to the head during clashes between Palestinians and residents of Rafah at a time when Israel was still in control of the Gaza-Egypt borders. His father said the injury affected his mental abilities.