Waheguru Ji ka Khalsa Waheguru Ji Ki fateh.
As far as I have read Sikh historical accounts there is no mention of any such Trials/judging/and execution of murders/rapists etc.
The only deaths took place on the Battlefields only..and GURU JI always gave the opponent the chance to fire the first few blows ( vaar) shot etc.....handicap !!
IMHO the GURUS were not sitting in judgement over criminals....any criminal who approached the GURU was Forgiven and probably never committed any such crime again ( such was the Personality of the Gurus)...and secondly the GURUS came to Forge a perfect Human...not find faults and justice in the normal human world..that is the work of the Moghul rulers.
Even in the Maharaja Ranjit singh Ji's Rule, there is NO DEATH penality for anyone recorded. He forgave the Multan Governor umpteen times for rebelling agianst his forces...the Multani would rebel, fortify his fort and wage war, the Sikh Army would figth back, reconquer him and pesh him in front of the Maharaja...he would fall on his knees and beg forgiveness and the Maharaja would give him back his Raaj of Multan. This happened again and again but the Maharaja never lost hope in the man.
off topic another intersting fact about the Mahraja's UNIVERSAL and Fair rule..
I know a pakistani friend who is an academic living in lahore and he tells me so many of the BIggest and Most beautiful Mosques in Pakistan are the ones funded and restored by maharja ranjit Singh...but it is not politically correct to admit this in amUslim republic whereby a {censored} King has decorated the mosques and spent vast amounts much better than a muslim king ever did.
jarnail Singh