A French naval ship carrying specialist probes designed to detect black box pinger signals has arrived to the search area where the EgyptAir jet is believed to have crashed last week as search teams in the Mediterranean have picked up a beacon believed to be from the aircraft.

A week after the Airbus A320 crashed with 66 people on board while en route from Paris to Cairo, investigators have no clear picture of its final moments.

ALSEAMAR, a subsidiary of French industrial group Alcen, is providing equipment that includes three of its DETECTOR-6000 systems, designed to pick up black-box pinger signals over long distances up to 5 km (3 miles), according to the company’s website.

The French company will conduct a deepwater search in “four or five” areas within the 5 kilometer search zone believed to contain the two black boxes, with the possibility of expanding the search zone should no signal be detected, sources on the investigation committee said.

Meanwhile, the chief investigator in the plane crash, Ayman al-Moqadem, said search teams have picked up a beacon.

He said this narrows down the search to a 5 kilometer radius. He insisted that this doesn’t mean the flight data and cockpit voice recorders — the so-called “black boxes” — have been found.

Al-Moqadem said finding the boxes requires highly sophisticated technology.

He said the signal that was picked up comes from one of the devices on the plane transmitting its location. He spoke to reporters on Thursday.

But sources close to the investigation said on Friday that no new radio signal has been received from the jet since the day it crashed.

A radio signal picked up on the day of the crash from the plane’s emergency locator transmitter (ELT) allowed officials to determine a broadly defined search zone, but nothing new has since been detected, the sources told Reuters.

“There has been nothing since day one,” a source familiar with the investigation said.