Islamabad ? The back-to-back arrests of two top Pakistani Taliban members are another blow to a militant network reeling from the apparent killing of its chief in a CIA missile strike and could be a fresh sign of infighting over a possible successor.

Washington will be keen to exploit any disarray within the ranks — and the prospect that Taliban leaders could turn on each other — in its campaign against an al-Qaida ally behind attacks in Pakistan and neighboring Afghanistan.

One of those arrested, Pakistani Taliban spokesman Maulvi Umar, told interrogators Tuesday that the movement’s chief, Baitullah Mehsud, had been killed in the Aug. 5 strike close to the Afghan border, according to an intelligence official who took part in the questioning. He spoke on condition of anonymity because he was not authorized to speak to the media.

U.S. and Pakistani officials have said they were almost certain that Mehsud had been killed in the attack.

But final confirmation has been hard because authorities have not seen his body and at least three Taliban operatives — including Umar himself — had called media organizations soon after the attack to say he was still alive.

Visiting U.S. envoy Richard Holbrooke said Mehsud’s apparent death had sparked a “succession crisis.”

“The chaos benefits us, but it doesn’t mean that this thing is over,” he told CNN in comments reported Tuesday.

Militant violence has spiraled in Pakistan over the past two years, but tough military action — backed by a public sickened by suicide bombings and concerned over Taliban territorial gains — has put the Islamic extremists on the back foot — even as Taliban attacks soar across the border in Afghanistan.

Umar’s capture came on Monday night — the same evening as that of another Mehsud aide, Qari Saifullah, who was picked up as he was being treated in a private hospital in the capital, Islamabad, intelligence officials said.

Saifullah told police he had been wounded in an American missile strike in South Waziristan, the police said. It was unclear if it was the same strike believed to have killed Mehsud.

Accounts of Umar’s arrest in Mohmand tribal region, which lies further north, suggest local tribesmen were emboldened to help authorities in the wake of Mehsud’s reported demise.

The Taliban spokesman was captured along with two associates in a village close to the Afghan border, said Javed Khan, a local government administrator.

Tribal elders had assisted troops in locating Umar in the village of Khawazeo, another intelligence official said. Before Mehsud’s death villagers did not dare tip off authorities about his presence out of fear of Mehsud, the official said, also on condition of anonymity.

As the Taliban mouthpiece, Umar initially operated relatively openly — a reflection of Pakistan’s previous reluctance to tackle the group.

After Tehrik-e-Taliban Pakistan was formed by Mehsud in 2007 as an umbrella organization for various regional and tribal militant movements, Umar frequently called journalists to claim responsibility for terrorist attacks in Pakistan.

Reporters had his home and cell phone numbers. Umar would occasionally summon Pakistani reporters stationed in Khar, the main city in Bajur tribal region, for news conferences at his headquarters in nearby Mamund town.

But after the army began an offensive in April, Umar changed phone numbers frequently. He never appeared in public, but still continued to telephone the media with messages from the Taliban leadership.