An Argentinian judge was allegedly caught kissing a convicted murderer on prison CCTV after trying to get him a reduced sentence.

Mariel Suarez is being investigated after visiting Cristian ‘Mai’ Bustos, who is serving time for shooting policeman Leandro Roberts in 2009.

Footage shows her seemingly locked in an embrace with the ‘highly dangerous’ killer who she also shared tea with at the Provincial Penitentiary Institute of Trelew.

She was the only judge involved in the case to vote against the life term he received, instead arguing for a lesser punishment.

But Ms Suarez, who claims she is writing a book on the prisoner, insists there was ‘no kiss’ and they were ‘talking close up to avoid being overheard’.

She added that they have ‘no sentimental relationship’ and she voted for reduced jail time because she ‘believed the version of events he gave at his trial’.

Court officials said they would probe her ‘inadequate behaviour’ after a video of the December 29 visit was made public.

The Superior Court of Justice of Chubut has now opened administrative proceedings into the judge’s behaviour, alleging that she engaged in inappropriate behaviour with the recently convicted man.