For foreign journalists arriving in Homs, the makeshift press centre near a hospital in the Baba Amr neighbourhood was supposed to be a refuge; a place to safely meet with colleagues and Syrian activists, seek security advice, find a decent meal and most important, a satellite signal to transmit stories home.
For veteran Sunday Times correspondent Marie Colvin and French photographer Remi Ochlik, however, the sanctuary turned deadly after an artillery shell struck Wednesday morning. The pair were killed by a rocket-propelled grenade as they tried to flee the building. The attack – the worst against journalists since the Syrian uprising began – wounded two other foreign reporters and eight Syrian activists.
"France holds the Syrian authorities responsible and accountable for the life of our national and our injured," said French Foreign Affairs Minister Alain Juppé.
The killings have raised the question of whether the technology the journalists and activists were using to transmit their stories also served as a beacon for Syrian government forces that sought to target them. The press centre was apparently the only place in the city with a 'live feed' for broadcasters and satellite phones emitting a near-constant signal. Syrian government forces could triangulate the location of the satellite transmission.
Intelligence agencies around the world track phone and satellite signals to target enemies. Syrian activists said they took specific measures to avoid being detected when using satellite phones, such as limiting the duration of their calls, and changing locations.
Communications between Syrian army officers intercepted by Lebanese intelligence staff suggest direct orders were issued to target the press centre where Ms. Colvin and others were transmitting, according to The Daily Telegraph. Any deaths would be blamed on crossfire with "terrorist groups." As a gathering place for dozens of opposition activists – not just journalists – it is impossible to tell whether one group or the other was being singled out.
Jean-Pierre Perrin, a Paris-based journalist who was with Ms. Colvin in Homs last week, said they had been warned the Syrian army was planning to shell the centre.
"A few days ago we were advised to leave the city urgently and we were told if the Syrian Army find you they will kill you," Mr. Perrin told the Sydney Morning Herald.
Exactly how Syrian forces discovered the location of the press centre is also the subject of intense speculation. Mobile phone networks and electricity have been shut off in Homs for weeks. Satellite phones were virtually the only way to communicate with the outside world.
"We know the Syrians use sophisticated technology to monitor all kinds of communications, including satellite communication," said Peter Bouckaert, emergency coordinator for Human Rights Watch.
Earlier on in the uprising, many switched from Thuraya, a mobile satellite services operator based in the United Arab Emirates, to Inmarsat, a British company, and encouraged foreign journalists to do the same because they felt its signal was more secure.
Thuraya had previously stated the company had "conclusive evidence" that Libya jammed its signals during the civil war there, and thought them susceptible to monitoring.
"A number of people I knew who used Thurayas would get caught. In Damascus, I would get into a car, talk for 10 minutes while I drove around, then turn it off," said Rami Jarrah, a Syrian political activist who fled to Egypt with his family during the crackdown.
"Inmarsat is the one we used in Homs. Until Wednesday nothing ever happened," he said.
Mr. Jarrah believes Syrian forces could have discovered the location of the press centre by less high-tech methods.
"It's also possible that someone revealed where the place was. A lot of journalists come in and out and we can't be sure exactly who all of them are. Anything is possible," he said.
Brian Conley, director of Small World News, which has trained citizens to become journalists in Iraq, Libya and Syria, advises journalists using satellite phones in war zones to keep transmissions as short as possible because "transmissions can be triangulated with affordable, even homemade tools."
"My sense is that if that makeshift media centre had been there for a couple of hours then yes, it's definitely possible they could have been targeted using this technology," he said.
Ms. Colvin would have used a satellite signal to access the closed Web forum where she wrote her last post on Tuesday.
"I think the reports of my survival may be exaggerated," she wrote.