No one was wounded in the attack, which occurred around 2 a.m. and destroyed part of the lab in the Neder-Over-Heembeek section of Brussels. Five people were arrested nearby but were released after questioning; the police are looking for the attackers.
“The possibility of a terrorist attack has not been confirmed,” Ine Van Wymersch, a spokeswoman for the Brussels prosecutor’s office, said at a news conference. “It goes without saying that several individuals would benefit if elements from their legal cases were destroyed. The investigation is ongoing, and all possible scenarios are being considered.”
The target of the attack was the National Institute of Forensics and Criminology, which is part of the federal justice department and is Belgium’s center for forensic research, including the examination of biological and ballistic evidence. The institute handles thousands of cases a year for the federal police and the Belgian intelligence service, and it houses the country’s DNA database.
On March 22, three suicide bombers attacked the Brussels airport and a subway station in the city, killing 32 people in the worst act of terrorism in Belgium’s history. The bombers were part of a cell of Islamic State fighters who were involved with the terrorist attacks in and around Paris on Nov. 13 that killed 130 people.
Hair samples from Salah Abdeslam — the sole surviving participant in the Paris attacks, who was captured in Brussels on March 18 after an intense manhunt — were analyzed at the DNA center.
The failure to connect the dots before the March attacks and a history of worrisome security lapses at Belgium’s nuclear facilities have exposed profound vulnerabilities in the nation’s security system. The country’s governance is divided along regional and linguistic lines, hampering the collection and sharing of intelligence.The attack on the crime lab could hinder police and intelligence officials as they pursue suspects and monitor threats. Officials cautioned that they were not yet certain of the extent of the damage, but Ms. Van Wymersch said, “The damage to the building is severe.”
Because of the late hour, no guards or other employees were at the site, which is surrounded by several fences and is under video surveillance, when it was attacked, Ms. Van Wymersch said.
How the attackers managed to breach the fences and reach the crime lab is under investigation.
“Several perpetrators forced their way onto the N.I.C.C.’s premises with a car and were able to reach the building, more specifically the wing where the laboratories are situated,” Ms. Van Wymersch said, using the Dutch abbreviation for the institute. “At this time, we cannot provide more information concerning the modus operandi since the building is not yet accessible and examinations cannot be conducted at the scene.”
Ms. Van Wymersch denied reports in the Belgian news media that the attackers had used their vehicle as a battering ram to force their way into the building. The attackers did, however, manage to make their way through several security fences, drive up to the laboratory and set the building on fire.
“Witnesses say that they heard explosions,” Ms. Van Wymersch said. “The origin of these explosions has not been determined yet.”
On Monday, a crane lifted the charred wreckage of the vehicle from the scene of the attack, while heavily armed police officers patrolled the site. The lab is in an industrial area adjacent to a canal linking Brussels with the city of Charleroi to the south.
Ms. Van Wymersch said that a bomb disposal unit had been sent, along with arson investigators. For now, the case is being handled as an arson investigation, so it is being dealt with by the Brussels prosecutor’s office. If the case is deemed to involve terrorism, it may be transferred to the control of the federal prosecutor.
A senior Belgian counterterrorism official, who spoke on the condition of anonymity because the investigation is continuing, said he was surprised that the site was not better guarded, given how much is stored there.
The security breach could be an embarrassment for Prime Minister Charles Michel, who returned from a summer vacation last week and declared that security would be the government’s main focus over the next few years. As part of the drive, Mr. Michel announced a number of legal changes, as well as additional personnel and funding for the police and intelligence services.