A firm of private detectives that hired psychics to help the hunt for Madeleine McCann is being investigated by police for allegedly breaking Portuguese laws on criminal cases.

The company, Strongwood, claims that it is being funded by donations from more than 100,000 people to carry out inquiries into the disappearance of Madeleine from her bed in the resort of Praia da Luz 114 days ago.

However, Portuguese detectives have contacted officers in the Netherlands complaining that the company has broken laws that mean that only police can investigate criminal cases.

Strongwood, which is registered with the Dutch Ministry of Justice as a private investigation company, said that it had received donations totalling more than a team of three private detectives, an expert in children with a “special disorders” and a person with “special abilities” to Praia da Luz at end of last month.

A report of its findings concluded that Madeleine could have died before 7p.m. on the night that she went missing. Madeleine’s parents, Kate and Gerry McCann, have insisted that she was alive at 9 p.m. The company also claimed that the child was killed in her apartment before being taken to a beach in a white van where her body was dumped.

Nico van den Dries, chief executive of Strongwood, said that the company had been sharing information with Portuguese detectives and had not been told it was an offense to investigate criminal cases.

“We were asked to look at the case because some clairvoyants from America and the Netherlands were giving evidence to the Portuguese police and they were not following them up,” he said. “We are just doing it for the the expenses. We have been co-operating with the Portuguese and they have not said it is against the law.”

Inspector Olegário Sousa, of the Polícia Judiciária, said: “The investigation in Portugal only can be done by police forces. As the collection of funds was done in a foreign country, only the police in Netherlands can pursue what is clearly a fraud. No private detectives had worked with us or with our British colleagues.”

Willem Melius, from the Politie Zaanstreek-Waterland in the Netherlands, said: “In Netherlands the investigation of crimes is for justice and police but in case of missing persons it is different (but only inside the country). As soon as they discover it to be a crime they should alert the police. If Strongwood appears not to obey the rules the Justice Department will take steps.” Dutch police are already investigating a letter and map sent to an Amsterdam-based newspaper, De Telegraaf, which claimed to identify the location of Madeleine’s grave in the Algarve. Portuguese police searched the site but found no trace of Madeleine.

Madeleine’s father yesterday attacked police leaks that have fueled “preposterous” speculation about what happened to his daughter. McCann said he was disappointed that so much information had made its way into the public domain.