Updated

Pakistani police on Thursday released a sketch of a possible suspect in the kidnapping of an American development expert, as public silence from his abductors has added to fears about his fate.

Warren Weinstein, 70, was abducted early Saturday after gunmen tricked his guards and broke into his home in the eastern city of Lahore. He was the country director in Pakistan for J.E. Austin Associates, a U.S.-based firm that advises a range of Pakistani business and government sectors.

The black-and-white sketch released to the media shows a lean young man with short dark hair and a stubbly beard. Police did not name him. Investigators have been talking to Weinstein's guards and driver to reconstruct the scene and get details about the abductors.

Police officials could not be reached for comment Thursday. Earlier this week they said there has been no demand for ransom or any other word from Weinstein's abductors, hampering efforts to free him.

Pakistani authorities have said they have been unable to determine who kidnapped Weinstein.

Kidnappings are common in Pakistan, and foreigners are occasional targets. Criminal gangs are suspected in most abductions, but militants are also believed to use the tactic to raise money through ransoms.

In some kidnappings, victims are taken to Pakistan's remote tribal regions along the northwest border with Afghanistan, hundreds of miles from Lahore, before the abductors make themselves known. The Pakistani government has little reach in the tribal areas, where Taliban and other militants operate.

Weinstein worked in Pakistan for several years and spoke a fair amount of Urdu. He has a home in Rockville, Maryland. His wife and other relatives have not responded to requests for comment.

J.E. Austin Associates has stressed Weinstein's commitment to Pakistan's economic development and said he worked with a wide range of Pakistani government agencies, including the Pakistan Furniture Development Company and the Pakistan Dairy Development Company.

The company also said Weinstein is in poor health and provided a detailed list of medications, many of them for heart problems. It implored the kidnappers to provide the medicines to the development expert.