PARIS Hilton's billionaire grandfather donated money to the election campaign of the sheriff who released the 26-year-old American hotel heiress from jail, it has been revealed.

The contribution from William Barron Hilton, 78, co-chairman of the Hilton Hotel chain, to Sheriff Lee Baca's re-election campaign is revealed in financial records.

A friend of the Hilton family said the temporary release of the heiress last week may have been a "quid pro quo".

"A member of her family has been a contributor to Baca's campaign and this may have been payback time," the friend said.

"Her entourage initially were confident she would be out of jail in a few days."

Mr Baca, who has faced heavy criticism for attempting to overrule the judge in the case, has in the past been accused of favouritism towards the Hollywood elite.

A spokesman for Hilton declined to comment on the report, as did officials for the sheriff's department.

Hilton, sent to jail for violating probation in a drink-driving case, will finish her sentence in the prison medical ward where she ended up after a day of house arrest.

New reports today said that Hilton's health collapse last week was caused by dehydration.

"She didn't eat or drink a single thing for three days because she didn't want to use the toilet," a source also told the New York Daily News, adding that Hilton suffered from claustrophobia and hyperventilation.

"She was absolutely terrified that one of the guards or staffers would get her with the cellphone cam and it would wind up on the Internet," a source identified as a Hilton insider told the newspaper.

"She cried the entire time, and that wasn't helping the dehydration," the source told the paper.

Hilton is being given psychotropic drugs, TMZ reported on Saturday, citing law enforcement sources.

Psychotropic medications affect a person's emotions and behaviour and include drugs like lithium, which is taken for depression, and Valium, which eases anxiety.

Hilton, who was dragged sobbing back to jail, said being in prison was the hardest thing she had ever done, but she would not appeal her sentence.

She was initally sentenced to 45 days in jail in May for violating her probation and driving on an suspended licence. That was reduced to about three weeks for good behaviour before she even started her sentence.

Her early release last Thursday, after just three days in jail, triggered a wave of outrage and an angry judge demanded she be brought back to court on Friday, when he ruled she had to go back to prison.

Images of a dishevelled, distraught Hilton, far from the cool, glamorous blonde seen gracing catwalks and red-carpet soirees, were seen around the world as she was handcuffed by police and brought before Judge Michael Sauer.

Mr Baca had released Hilton. tagged her with an electronic ankle bracelet, and ordered her to serve out her sentence under house arrest for unspecified "medical reasons".

Stunned prosecutors filed a petition in protest and on Friday Judge Sauer ordered Hilton back to jail to serve out her sentence.

Hilton apparently broke down, wailing "mum, mum, mum", as the judge ordered her back to prison saying "the order is final and forthwith."

Her finale statement was

"I would hope going forward that the public and the media will focus on more important things, like the men and women serving our country in Iraq and other places around the world."