A married woman who was having an affair with a fellow skydiver plunged 13,000 feet to her death after her love rival and best friend tampered with her parachute, police say.

Els Van Doren, 37, fell to earth in a garden in front of a group of onlookers. Els Clottemans, 22, has been charged with her murder.

Minutes earlier the pair had joined hands in a star formation with two other skydivers including Clottemans’ boyfriend, a Dutchman named only as Marcel, who police say was having an affair with Van Doren.

While he and Clottemans broke away at 4,000 feet when their parachutes inflated, Van Doren, a mother of two, was unable to open either her main parachute or the reserve and crashed to her death in the town of Opglabbeek, Belgium.

Her final moments were filmed by her own head-mounted camera.

Wally Elters, a witness at the aerodrome from which the fatal flight departed, said: “I was working on my plane when I heard someone on the ground screaming and pointing to the sky.

“I looked up and saw a black spot falling quickly to the ground. It was wriggling about and it was pretty obvious it was a person.

“Above it were three people in parachutes coming down slowly. Then it hit the ground. It was an appalling moment.”

Police say that video footage taken by Van Doren as she tried to open her parachute provided evidence that led them to suspect that a fellow club member had sabotaged the equipment. A spokesman said: “A close inspection of the parachutes leads us to believe they had been meddled with.”

An employee at the airfield in Zwarteberg added: “It is very rare for one parachute not to open, but for two to fail is virtually unheard of.”

At Van Doren’s funeral, about 1,000 people heard her sister deliver a bitter eulogy. “You did all you could during that final jump to save yourself,” she was quoted as saying in the Belgian press. “But someone did not want you to live.”

Clottemans was arrested and charged after a two-month investigation. She denies the allegations but is being held in custody before a court appearance later this month.

Police became increasingly suspicious of Clottemans after discovering the affair between Van Doren and Marcel. All three had skydived together for several years.

Clottemans, a secretary, is understood to have attempted suicide hours before being brought in for questioning by detectives for a second time last month. She is said to be suffering from a personality disorder and is receiving treatment.

Police have also disclosed that Clottemans had previously been arrested for attempting to run over an American boyfriend. He escaped injury and she was released without charge.

According to the Belgian media, Marcel tried to arrange his liaisons so that neither woman found out about the other. His affair with Clottemans began a year ago and he would spend Friday evening through to Saturday morning with her.

In the afternoon, he would meet Van Doren after she had spent the morning working in her husband’s jewelry shop. Their relationship had begun some years earlier and the two would spend the night in nearby Eindhoven, before returning to the skydiving club the next day.

Despite Marcel’s precautions, Clottemans appears to have found out about her rival, although Van Doren was unaware that he was also involved with her close friend.

A statement from the public prosecutor said: “A thorough investigation of the available evidence and analysis of the motive provide sufficient reason for arresting the suspect. The investigating magistrate charged her with murder, issued an arrest warrant and had her locked up in Hasselt prison.

“In order not to jeopardize the smooth running of the investigation, no further information will be supplied. As has already been suggested in the media, the motive for the crime is most probably in the passionate area. The accused denies the charges.”