Three vehicles belonging to BirdLife volunteers were found ablaze in Buskett by the police early yesterday morning.
The cars were destroyed but no one was hurt and neither did the surrounding environment sustain any damage, the police said.
They said they were informed that the three cars, a Ford Fusion, a Honda Odyssey and a Pajero Jnr, were on fire at about 6.20 a.m. The police did not specify who the cars belonged to or how they caught fire.
BirdLife Malta executive director Tolga Temuge, who was on the scene of the incident, said two of the torched cars belonged to BirdLife council members and the third, bearing a diplomatic number plate, belonged to an American, who started voluntary work a few months ago.
Mr Temuge said the three volunteers were carrying out scientific ringing studies in Buskett. They arrived on site at about 5.45 a.m. and headed off to a nearby field to start their work.
"Just a few minutes later they heard a bang. Within 15 minutes, fire engines and the police arrived on the scene," Mr Temuge said, adding that he was informed by the police that it was probably a criminal act.
"It is not the first time such a thing has happened and no one has ever been brought to justice," Mr Temuge said, maintaining that a "dangerous" message was being conveyed that the criminals could get away with it.
He said BirdLife had sent a letter to the Police Commissioner, copied to the Office of the Prime Minister and to Environment Minister George Pullicino, 10 days ago, informing them about "messages with an increasingly threatening tone" posted on the website of the Hunters, Trappers and Conservationists Federation (FKNK).
BirdLife, he said, had requested action by the relevant authorities but has not yet heard from the police. "We demand urgent action from the government to bring criminals to justice," Mr Temuge insisted.
The fire was put out by Civil Protection Department personnel who were called on site. Duty Magistrate Consuelo Scerri Herrera was informed of the case and appointed various experts to assist her in her inquiry, the police said.
Police investigations continue.
Alternattiva Demokratika chairman Harry Vassallo yesterday expressed solidarity with BirdLife and its members, calling the incident a "cowardly" and "terrorist" attack to intimidate and shut the mouths of those who were doing good.