Where is "the man in the hat" from the Brussels bombings?
BRUSSELS --Belgian investigators released new images Thursday of a key suspect in the Brussels bombings.
They asked the public for help finding him -- a sign, perhaps, that their investigation is coming up short.
We don't know his name and his face is a blur, but if he's caught, "the man in the hat" -- as he's now known -- could reveal vital information about ISIS cells in Europe.
The two other men in a security camera image blew themselves up in Brussels' airport, killing 16 people. Another 16 people died in a subsequent explosion at Brussels' Maelbeek subway station.
The new video shows the third man walking away, and then into the heart of the city. At one point he breaks into a slow jog, but the rest of the time he appears calm.
His distinctive jacket disappears in the later videos, and police hope that if it's discovered, it could help them find him.
He's last seen nearly two hours after the airport bombings in the Schaerbeek neighborhood, where a police raid targeted the apartment the three men set off from, finding bomb-making materials and an ISIS flag.
After missing clues that an attack might be imminent, the Belgian authorities are under pressure to find the man in the hat -- but he could be hiding in plain sight.
Salah Abdeslam, the suspected logistics man behind the Paris attacks in November, was able to hide out in Brussels for four months before he was finally captured.
It's thought he relied on friends in the neighborhood where he grew up -- an area that's now become infamous as a breeding ground for extremists.
Intelligence officials across Europe are searching for ISIS recruits, including those with direct links to the Brussels and Paris attacks. Police in Denmark on Thursday arrested four people suspected of traveling to Syria to join ISIS.