The Office of the United Nations High Commissioner for Human Rights had voiced concern over reports of security force abuses in Venezuela, and this month the Venezuelan conference of Roman Catholic bishops objected to “the brutal repression of political dissent.”

“The government is wrong to want to resolve the crisis through force,” the bishops said.

Here in Valencia, Venezuela’s third largest city, Geraldín Moreno, a student, was standing outside her apartment complex on Feb. 19, banging a pot in protest, when soldiers rode up on motorcycles, according to her father, Saúl Moreno. She fell trying to run into the complex.

Witnesses said that a soldier got off his motorcycle, pointed his shotgun at her head and fired. The hard plastic buckshot slammed through her eye socket into her brain, her father said. She died after a lengthy surgery on Feb. 22, eight days shy of her 24th birthday.

“The pain will never go away,” Mr. Moreno said. “Every day her absence is greater.”

Mr. Gregory, who said he had been detained with 10 others, had gone to a protest here on Feb. 13 with friends Juan Carrasco, 21, and Jorge León, 25, but when they saw soldiers shooting tear gas and shotguns they ran back to Mr. León’s car. According to the men, soldiers surrounded the car, broke the windows and tossed a tear gas canister inside. Mr. Gregory said that a soldier fired a shotgun at him at close range while he sat in the passenger seat, hitting him in the arms and the back of the head.

The men said they were then pulled from the car and beaten viciously. At one point, Mr. Gregory said, a soldier smashed their hands with the butt of his shotgun, telling them it was punishment for protesters’ throwing rocks. The men said that the soldiers set fire to Mr. León’s car.

They were loaded into a truck with other detainees and driven to a National Guard post. One of the detainees, Oswaldo Torres, 25, a salesman in a brake shop, said that the soldiers pretended he was a soccer ball and kicked him over and over again. The men said they were handcuffed together, threatened with an attack dog, made to crouch for long periods, pepper sprayed and beaten.