LUCKNOW, India — Police arrested a third suspect Saturday in the gang rape and slaying of two teenage cousins found hanging from a tree in northern India, as a top state official said he was recommending a federal investigation into a case that has triggered national outrage.

The three suspects detained in the attack in Uttar Pradesh state are cousins in their 20s from an extended family, and they face murder and rape charges, crimes punishable by the death penalty, said police officer N. Malik. Two other suspects from the same village are also being sought, he said.

Facing growing criticism for a series of rapes, authorities in Uttar Pradesh, which has a long-standing reputation for lawlessness, also arrested two police officers and fired two others Friday for failing to investigate when the father of one of the teenagers reported the girls missing earlier in the week.

India has a long history of tolerance for sexual violence. But the gang rape and killing of the 14- and 15-year-old girls – which was followed by TV footage showing their corpses swaying as they hung from a mango tree – caused outrage across the nation. The father who reported the girls missing, Sohan Lal, has demanded a federal probe.

“I don’t expect justice from the state government as state police officers shielded the suspects,” said Lal, a poor farm laborer who refused to accept a payment of $8,500 offered by the state government. He said Saturday that he would accept no financial assistance until the Central Bureau of Investigation, India’s FBI, takes over the case.