Both Schalke 04 and the German Football Association (DFB) launched investigations on Monday to find the supporter who threw a lighter which badly injured Royal Blues' assistant coach Sven Huebscher.

"There are signs the perpetrator will be found," Schalke board member Peter Peters told daily newspaper WAZ.

"We highly recommend that the person responsible gives himself up to police," Peters added, which would mean a milder punishment if there is a conviction.

Roberto di Matteo's assistant Huebscher was left pole-axed and bleeding from a head wound on the sidelines after being struck on the head by a lighter on Saturday at Gelsenkirchen's Veltins Arena.

The metal lighter was thrown from a section of the crowd behind the Schalke bench in the late stages of Saturday's 2-1 home defeat by Cologne which left the Royal Blues sixth in the league.

Schalke will have to answer to the DFB, whose disciplinary committee has launched its own investigation.