French police investigating the death of a pregnant woman mauled to death by dogs while walking in the woods have carried out DNA tests on 67 dogs to try identify those that attacked her.

Elisa Pilarski, 29, was found dead on Saturday in Retz forest, about 55 miles north-east of Paris, after taking one of her own dogs for a walk. A hunt with hounds was under way in the forest at the time.

A postmortem concluded that she bled to death after several bites to her arms, legs and head.

An investigation has been launched against persons unknown – a common procedure in France at the start of a case – for manslaughter due to carelessness or negligence.

Frederic Trinh, the public prosecutor leading the investigation, said on Thursday that DNA tests had been carried out on 62 dogs from the hunting club and five belonging to Pilarski and her partner. He said police as yet had no main line of inquiry.

He confirmed Pilarski phoned her partner at work before the attack to tell him she had come across “threatening dogs”.

In a Facebook message she wrote that a German shepherd was on the prowl. Trinh said police had yet to identify that dog.

Pilarski’s partner told the French TV channel BFM that when he arrived on the scene about 45 minutes later he first encountered hunting hounds and a rider. He then saw a pack of “around 30” dogs near a ravine where he found her body as well as the couple’s dog Curtis, which he said had been bitten on the head.

Sobbing during the interview, he told BFM that what he had initially mistaken for a log turned out to be Pilarski’s bare stomach. She was “entirely undressed” and had been “bitten all over”, he said. “It can only be the hunt.”

According to the Courrier Picard, a local newspaper, the hounds were hunting deer.

Hunting associations have denied they could be to blame. The Paris-based French hunting association said: “Nothing shows the involvement of hunting hounds in the death of this woman.”

France has more than 30,000 hunts with hounds. The association said: “These dogs are trained to hunt a particular animal and obey man in all circumstances.”