* Militants deny official account of doctor's case
* Mysterious case strains ties with Washington
* U.S. seeks Afridi's release from jail (Adds details of charges)
By Saud Mehsud and Jibran Ahmad
DERA ISMAIL KHAN/PESHAWAR, Pakistan, May 31 (Reuters) - D eepening the mystery in a case that is straining Islamabad's relations with Washington, a Pakistani militant group said on Thursday it never had ties to a doctor who helped the CIA find Osama bin Laden, even though he was jailed for aiding them.
Last week, after Dr Shakil Afridi was convicted by a court in the Khyber tribal region near the Afghan border, Pakistani officials said the decision was based on treason charges for helping the CIA and conspiring against the state.
After that announcement rankled the United States, Pakistani officials said the doctor had a history of womanising, sexual harassment and assault and stealing, allegations that could not be independently confirmed.
A court document released on Wednesday stated that Afridi was imprisoned for 33 years for supporting the Lashkar-e-Islam (LI) militant group.
"There is no truth to this. We want to get him ourselves. If we get hold of him, we are going to punish him according to sharia law," Abdul Rasheed, an LI commander, told Reuters.
Rasheed said Afridi was a bad doctor who had mistreated people and that was why the militants wanted to punish him.
"He is a traitor, an enemy of Islam, a greedy blackmailer."
The comments are likely to raise new questions about Afridi's case, which has come to symbolise the strains in the alliance between Pakistan and the United States. U.S. officials hail Afridi as a hero who helped the CIA track down bin Laden.
The al Qaeda chief was killed by U.S. Navy SEALs in a raid in the Pakistani garrison town of Abbottabad in May last year.
U.S. Defense Secretary Leon Panetta suggested Afridi's sentence would hurt efforts to repair ties damaged by several events, including the unilateral raid that killed bin Laden.
Pakistani officials describe bin Laden's long presence in Abbottabad as a security lapse and reject suggestion that members of the military or intelligence services were complicit in hiding him there
U.S.-Pakistan cooperation is critical for weakening the Taliban insurgency in neighbouring Afghanistan.
Failure to do so could hurt President Barack Obama's re-election bid. The United States and Pakistan are deadlocked in talks over re-opening supply routes through Pakistan to NATO troops in Afghanistan - closed by Islamabad after a NATO cross-border air attack killed 24 Pakistani soldiers last year.
In Washington, government sources said the United States was making strenuous efforts to win Afridi's release from jail.
LED BY FORMER BUS DRIVER
Citing intelligence reports, the court document states that Afridi was "in league" with LI, providing it with funding and medical treatment for its leaders. It noted his "love" for the group's leader, Mangal Bagh, a former bus driver turned warlord.
LI is a relatively small militant group based in Khyber, one of seven ethnic Pashtun tribal districts along the border that have never come under full government control.
It is not allied with any of the other major militant groups operating in nuclear-armed Pakistan.
U.S. officials often describe Pakistan as an unreliable partner in the war on militancy and demand tougher action against militant groups. Critics also say the judicial system has failed to take decisive action. Convictions for terrorism are rare, with appeals dragging on for years.
Pakistan security forces face an array of militant groups which sometimes battle each other, but often share the goal of toppling the government and imposing shariah law.
LI had several bloody clashes with the al-Qaeda linked Pakistani Taliban, seen as the biggest security threat to Pakistan, one of the most unstable countries in the world.
Former and current Pakistani security and intelligence officials say Afridi was a poorly qualified doctor.
LI, which made similar accusations, could be attacked by other militant organisations if it is seen as having cooperated with Afridi, who is in his late 40s.
"We punished him three years ago after people complained about him. He conducted improper surgeries, sold poor quality medicines and blackmailed people," said Rasheed.
"We caught him, fined him and distributed that money to the affected people. His surgeries had disabled many people. The government is inept so it never acted against him."
Afridi was tried in a tribal administration court, under laws which do not carry the death penalty. Some analysts said the decision was made to appease the United States.
The Pakistani Taliban had a similar interpretation.
"Shakil Afridi is a traitor, and the only punishment for a traitor is death. Pakistan's rulers are afraid of America, so they are not sentencing him to death," Pakistani Taliban spokesman Ehsanullah Ehsan told Reuters.
"Dr. Shakil Afridi caused the martyrdom of Osama bin Laden, who was a hero of Islam. If the Taliban get their hands on Shakil Afridi, we will cut him to pieces."
Afridi is in solitary confinement because authorities at the prison in the northwestern city of Peshawar fear militants or others may try to kill him.
"It is, therefore, necessary that under the present circumstances, the doctor should be given maximum security. He should be made secure," said his lawyer Samiullah Afridi. (Additional reporting by Mark Hosenball in Washington; Writing by Michael Georgy; Editing by Ron Popeski) (Additional reporting by Mark Hosenball in Washington; Writing by Michael Georgy; Editing by Ron Popeski)