The first ransom demand came in a text message on Sami al-Izoo’s phone 10 days after he witnessed his brother being kidnapped, forced into a truck with dark tinted windows by six masked men.

Next came a video in which he said his brother, Abdulrazaq al-Izoo, 60, appeared with his hands tied and a black bag over his head, screaming as he was hit with a stick. Since then, the videos and threats have continued to buzz Mr. al-Izoo’s phone as he struggles to raise the $400,000 that the kidnappers want.

Mr. al-Izoo is not rich and says he does not know why his brother was targeted. He sold a couple of cars and is trying to sell his land, but he doubts that will be enough to cover the enormous sum. “If I sell everything I have, I won’t reach that amount,” he said from his home in Talbiseh, a suburb of the city of Homs, in central Syria.

The abduction is one of a spate of kidnappings in Syria since the rebel coalition that ousted President Bashar al-Assad in December took over. One of its first acts was to dismiss — at least temporarily — all government police and security officials.

The security forces were instruments of Mr. al-Assad’s oppressive regime, but some Syrians have criticized the decision to dissolve them. Though the new government has replaced some of the officials with its own members and quickly trained police officers, that force cannot sufficiently cover the country.