OUR STAFF REPORTER LAHORE The police investigating into the kidnapping of US?expert Dr Warren Weinstein have reached a dead end as the security experts grilling the suspects have been left empty-handed. Dr Warren, Country Director for US-based firm JE Austin Associates, was abducted from his office-cum-residence in Model Town, Lahore before dawn on August 13. He had been working in Pakistan for last seven years. The investigators are empty-handed as they could not get any useful information even after investigating all the four guards and the driver of Dr Warren, a police officer told this report on Wednesday. According to sources, one of the kidnappers hit Dr Warren in the head with the butt of the pistol when he tried to put up resistance. They took him along with them while his head was bleeding. The investigators are even not clear whether the men who kidnapped the US development expert were criminals or militants.