Police in Bonn, Western Germany are searching for a machete-wielding “African” appearance male speaking “broken English” who raped a 23-year-old in a meadow while threatening to kill her boyfriend if he intervened.

Investigators said Wednesday they have received more than 150 tips from the public in relation to the attack, which took place in a meadow in the Siegaue conservation area and left the student and her boyfriend “very affected”.

Just after midnight on Sunday, the assailant approached the couple’s tent and slashed it open with his machete before demanding cash. Threatening to kill her boyfriend if he tried to do anything, the man then ordered the woman to leave the tent, and proceeded to rape her.

“Both victims were in a state of mortal fear”, said police spokesman Robert Scholten. He told Bonn’s regional newspaper General-Anzeiger that the 26-year-old boyfriend managed to notify police and rescue services of the rape as it happened, using a low voice.

The young woman was admitted to hospital overnight, and both victims are now in the care of victim support services. Police searched the surrounding area of the crime scene with a helicopter and search dogs but were unable to find the assailant.

A party was being held a few hundred metres away from where the attack took place and witnesses came forward to say they had noticed a man of African appearance skulking around. Investigators also received tips that he’s been sighted in Beueler Rheinufer and Nordbrücke.

Specialists at the German Federal Criminal Police (BKA) produced a picture of the suspect based on witness descriptions, and police are appealing for further information that could lead to his arrest. He is described as about 5′ 9″, dark-skinned, and to have spoken in broken English.

Although the man’s DNA is not on the police system, Scholten said: “Because of the way in which the attack was carried out, we can’t rule out the possibility that the perpetrator hasn’t been previously active in the fields of violence and robbery.”

“It’s necessary that we compare the incident with other cases, and other violent acts,” he added.