They also sent false email messages to Schrier’s family and friends that said he was safe and still working in Syria. His mother realized that the messages — filled with spelling and grammatical errors –were fake and agonized over what to do. Schrier urged the families of the missing to not give up.

“Until someone shows you proof that your loved one is dead, you have to assume they’re alive,” Schrier said in an email. “A lot of people who knew about me thought I was dead — and look what happened.”

The wave of kidnappings is also exposing an unintended consequence of a tactic widely used in Iraq and Afghanistan: media blackouts in kidnapping cases. Security experts and law enforcement officials generally recommend that abductions be kept secret in the hope that victims can be rapidly found or terms quickly reached. Publicity can also inflate kidnappers’ ransom expectations.

Of the 30 cases in Syria, the families of a dozen captives requested that the abductions be kept secret or could not be reached, according to the Committee to Protect Journalists. In an effort to warn other journalists about how dire the situation has become in Syria, the group took the unusual step of disclosing the total numbers of kidnappings in Syria but withheld the captives’ names and nationalities.

“Blackouts can have an unintended consequence of camouflaging the actual dangers of the situation,” Rob Mahoney, the committee’s deputy director, told me Friday. “It was in the interest of everyone that the scale of the problem be demonstrated.”

Others argue that keeping kidnappings secret decreases pressure on governments. Without demands for action from the public, government officials have no need to act.

Four American journalists are being held captive or missing in Syria. Austin Tice, a freelancer for the Washington Post, went missing near Damascus in August 2012. James Foley, a freelance reporter for GlobalPost, went missing in northern Syria last November. The families of two other Americans have reportedly requested that their cases be kept secret.

(In 2008, two Afghan colleagues and I were abducted by the Taliban and held captive in Afghanistan and Pakistan for seven months. My family and my employer, The New York Times, requested a media blackout.)

As reporting has grown more treacherous, technological change has made it easier for freelancers to shoot videos and photographs and instantly file them to news agencies. But freelancers, if they are abducted, lack the backing of large news organizations that can hire security consultants and take other steps to aid captives’ families.

In an effort to discourage freelancers from entering Syria, The Sunday Times of London announced in February that it would stop accepting photographs from freelancers who entered the country without a prearranged assignment with the newspaper. The paper had already suffered a tragic loss—its award-winning American correspondent, Marie Colvin, died covering the siege of Homs last year.