Pirate Party politician Gerwald Claus-Brunner, 44, (pictured) was found dead in his Berlin apartment on Monday

One of the most prominent figures in Germany's Pirate Party is believed to have taken his own life hours after losing his seat in Berlin's regional parliament.

Gerwald Claus-Brunner, 44, was found dead in his apartment in the suburb of Stieglitz, alongside the body of a younger man who had apparently been beaten to death.

The well-known politician was reportedly battling with an 'incurable illness' when he took his life, according to his social-liberal party.

His had also voiced his concerns about the party's dwindling voting numbers in the past few months ahead of Sunday's election - which saw him lose his seat to a rival.

Detectives are probing the deaths and officers said evidence suggested a murder-suicide.

The Pirate Party wrote on its website that Mr Claus-Brunner had been suffering from an 'incurable illness'.

'We do not know the exact circumstances, but we know that it was indeed an incurable sickness,' the party said.

They described the 44-year-old, who often sported a head scarf and overalls in parliament, as 'controversial'.

Mr Claus-Brunner, 44, was found dead in his apartment in Steglitz, south-west Berlin, alongside the body of another man, pictured are officials removing one of the bodies

The well-known politician was reportedly battling with an 'incurable illness' when he took his life, according to his social-liberal party

'Faxe, as we all called him, was always controversial, never simple and did not have it easy. Every one of us has a story to tell about him,' the statement read.

They signed off the message with 'Fare well, Faxe! We will miss you.'

The day before his death, the Pirates won just 1.7 per cent of the vote in the Berlin regional election, losing its seats in the assembly.

Detectives are probing the deaths and officers said evidence suggests the men committed suicide

The Pirates entered the regional parliament for Berlin's city state in 2011 and after Mr Claus-Brunner finished his first term, sources claimed he was 'morally and spiritually finished.'

Tagesspiegel reported that he hinted about his own demise during his last appearance at the assembly in June.

He said: 'In this current legislature, you will also stand up and have a minute of silence for me at the beginning of the plenary meeting.'

Asked what he meant, he added: 'You will light a candle for me. Something like that.'

He predicted the Pirate Party - which campaigns for total freedom on the internet - would no longer be part of the parliament due to their poor polling numbers.