President Obama on Monday signed into law better protections for Peace Corps volunteers, ending a long public campaign by volunteers who said the humanitarian agency did little to help victims of sexual assault.

The Kate Puzey Volunteer Protection Act of 2011 is named after a 24-year-old Georgia woman who was killed in 2009 while posted with the Peace Corps in a village in Benin, days after her confidential e-mails about a fellow teacher were mishandled. The suspects in the case have not gone to trial.

The bill was supported by the Peace Corps, unlike previous legislation that did not pass Congress. Many of the changes already had been adopted by the agency, whose director, Aaron S. Williams, acknowledged a “blame the victim” culture.

Volunteers who report wrongdoing will be protected, volunteers will receive better training on how to avoid attacks and advocacy for sexual assault victims will be stronger. The bill passed the House and Senate unanimously.

David L. Puzey, Kate Puzey’s brother, said supporters of the legislation had hoped for a guaranteed number of professional victim advocates. Instead, third-year volunteers will be trained and designated to act as advocates in each of the 77 countries where volunteers are posted.

“In the end, we were very happy with the final product,” he said.

The law does not address the Peace Corps’ law enforcement response to violent crime, which was moved in 2008 from the inspector general’s office to its own in-country staff, most of whom have little or no law enforcement training. Former volunteers and investigators have criticized the shift as a weakness in pursuing justice against perpetrators.

After rape victims and Puzey’s mother, Lois, recounted insensitive treatment by Peace Corps officials at a congressional hearing in June, lawmakers seemed convinced that tighter controls were needed on the 50-year-old agency founded by President John F. Kennedy.

Puzey was killed after telling Peace Corps officials that a Beninese man who taught with her at a school was molesting young girls.

The man is now accused of killing her, and he and two other suspects are in jail. Sen. Johnny Isakson (R-Ga.) recently traveled to Benin to put pressure on government officials to let the FBI reopen the investigation. An appeals court is expected to issue a ruling on the request soon.