An investigation showed that a crossbow attack at the Israeli embassy in the Serbian capital last month was the act of a lone extremist, a minister said on Monday.

On June 29, a member of a special police unit was shot in the neck with a crossbow outside the Israeli embassy in Belgrade after which he opened fire and killed the attacker.

“No broader organization has been identified in the preparation of the terrorist act,” and the attacker had no accomplices, Interior Minister Ivica Dacic told reporters on Monday.

The attacker belongs to the Wahhabi movement — a purist form of Islam that dominates in Saudi Arabia — whose followers can be found in many countries, Dacic said.

Security services continue to monitor their activities in Serbia, the minister added.

Dacic had earlier identified the attacker as a Serbian convert to Islam who had moved to Novi Pazar, a southern city with a long tradition in both Orthodox and Muslim history.

Serbian Prime Minister Milos Vucevic had slammed what he called a “heinous terrorist attack.”

After the attack, Serbia was put on red alert with an increased police presence, which led to a series of arrests and searches conducted at several locations.

Two men were arrested in the wake of the attack. It was not immediately clear from Dacic’s remarks whether they were released.