The notice, issued by the department on the instructions of Chief Minister Oommen Chandy, sought an explanation from Singh for his behaviour, official sources said.
The 1985 batch IPS officer had allegedly failed to acknowledge the presence of Chennithala by not saluting him at a passing out parade of women police personnel at Thrissur on July 11.
As soon as it was announced in the public address system that the minister had reached the venue, senior police officers on the dias stood up to receive him and saluted him.
However, ADGP Rishiraj Singh, in-charge of the Armed Forces Battalion, who was seated on a sofa, continued to do so and allegedly did not welcome the minister or salute him.
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When the incident became a talking point in the social media, Singh dismissed the reports as 'baseless'.
A photograph showing the ADGP seated went viral in the social media and it was alleged that he had shown disrespect by not standing up and saluting the minister.
Singh, who shared the dais with Chennithala at a function few days ago, had greeted the minister with folded hands.