The pro-Russian Chechen interior ministry said that Nourdi Elmourzayev, 50, was traveling alone in his car on Tuesday night when he was stopped at gunpoint by armed men and taken away.
Alkhan-Kala, a town of about 20,000 people southwest of the capital Grozny, has been the site of frequent clashes between Chechen rebels and government forces.
And the four teenagers, who were abducted by masked and uniformed men on 30 November, had been tortured and shot, interior ministry officials said.
Police officer killed
The ministry added that a police officer was killed and three others were injured when their automobile came under fire in Goudermes.
Meanwhile, the European Commission has expressed deep concern at the planned closure of a camp for Chechen refugees in Ingushetia.
"I am deeply concerned by the closure of yet another camp in Ingushetia, especially during the harsh Caucasian winter," said EU aid commissioner Poul Nielson on Wednesday, referring to the "imminent" closure of the Alina camp.
"I am deeply concerned by the closure of yet another camp in Ingushetia, especially during the harsh Caucasian winter"
EU aid commissioner
"It is the third camp to be closed in Ingushetia in 12 months, in addition to the closure of a camp in Chechnya last year," he said.
Nielson added that Chechen refugees had the right to "protection and assistance" in Ingushetia.
The European Commission is the main donor of humanitarian aid to the victims of the conflict in Chechnya, with more than $145 million allocated since the beginning of the second conflict there.
The EU executive's aid branch has spent at least $180,000 for infrastructure at the Alina camp, as well as funding the distribution of food, hygiene items, bed items and firewood for the winter.
However, the president of Ingushetia, Murat Zyazikov, last month denied that Chechen refugees were being forced out of tent camps in his republic on war-torn Chechnya's western border.