For hours, gunmen held captive a church group camping on a spiritual retreat.

They raped girls and beat boys. They stole their cellphones.

Finally the gunmen left; the youths wrapped themselves in blankets and walked five miles to find help.

The attack late last week outside Mexico City illustrates the mounting dangers — especially violence targeting women — in the Mexican state that until last year was governed by the man who will be the nation's next president.

The state of Mexico, which surrounds Mexico City on three sides, has seen an "alarming" surge in the number of murders and rapes of women, according to several human rights organizations. Much of that increase occurred during the governorship of Enrique Peña Nieto, whose six-year term ended last fall before he went on to win this month's presidential election.

"We identified a systematic pattern of violence against women, triggered by a lack of investigation, prosecution and punishment by the system of justice that exists in the state," a Mexican watchdog group, the National Citizens' Observatory of Female Murders, concluded this year.

The organization was rebuffed in its efforts to persuade the state legislature under Peña Nieto's government to issue an alert to women to protect themselves. It identified 1,003 slayings of women during Peña Nieto's term, roughly half of which went unsolved and largely uninvestigated.

In 2011, two women a day, on average, were slain or went missing in Mexico state, according to the organization.

In the camping incident, about a dozen gunmen invaded the eco-friendly Hummingbird campground where about 90 youths and adults were on a retreat sponsored by the Church of the Holy Trinity. The attackers held the group captive from late Thursday until the predawn hours of Friday.

One girl told Mexican television that the assailants pointed their guns steadily at the youths, forcing several girls into their tents, where they were raped.

Alfredo Castillo, state prosecutor, said five female members, three under the age of 18, were raped. He said Monday that one suspect had been arrested and several others "identified" and were being sought. Authorities were familiar with the group because of its past criminal activity, he said, adding that the isolation of the campground made it vulnerable.

"It was an area that was totally isolated, remote, wooded," Castillo told Milenio television. "They [the people on retreat] were looking to be completely out of contact with other people.... That's why there was no police presence."

Castillo, who has been quoted in news reports as saying women get killed and attacked in Mexico state because they use drugs, did not return calls to The Times.

In a report this month, Amnesty International said violence against women in the nation had reached alarming proportions.

"In recent years we have witnessed not only an increase in killings of women but a continuing routine lack of effective investigations and justice," the London-based human rights organization said.

In the run-up to his campaign for the presidency, Peña Nieto sought to portray his public security record in more positive terms than the reality would suggest. His government redefined "homicide" in a way that allowed officials to claim the number of murders had declined when, according to most experts, it had soared.

And his government used a legal loophole to assert that there were virtually no extortion cases in the state, when, in fact, Mexico state had one of the nation's highest rates of extortion, a favorite sideline crime of drug traffickers.

Perhaps the darkest mark on Peña Nieto's record was the 2006 incident in San Salvador Atenco, when nearly 30 women were arrested during a protest by peasants and then sexually assaulted by police while in detention.

Peña Nieto has since said it was necessary to use force to put down the protest but also recognized that abuses took place.

Yuriria Rodriguez, an activist with the observatory, said the lack of prosecution of women's slayings in Mexico state has led to a climate of impunity. "They want to close their eyes," she said.