Police are probing whether a tweet made by a DAP lawmaker's aide, criticising the arrests of May Day protesters, could incite people to commit offences against the government or threaten public tranquility.

"They are investigating the tweet under Section 505(b) of the Penal Code. (They want to know) why I made the tweet and if I had any hatred towards any organs of the state," Jay Jay Denis told Malaysiakini .

An offence under this law may result in a jail term of up to two years, a fine or both.

The research assistant to Klang MP Charles Santiago had published the tweet on Friday night, after reports that police were arresting participants of the rally against goods and services tax.

IGP Khalid Abu Bakar had warned him to watch his words.

Denis however is sticking with his guns and again criticised the top cop.

"I have a feeling the IGP has a very a poor command of English, which is why he needed the investigations to take place," he said when contacted after his statement was recorded in Bukit Aman this afternoon.

Told to surrender computer

Denis said the police probe coincided with his 32nd birthday.

"It was one of my better birthdays actually," he said.

He added that investigations were launched after a police personnel from the Dang Wangi district police headquarters filed a report on Saturday.

Denis will have to report back to Bukit Aman soon and surrender his laptop computer.

Meanwhile, Santiago told Malaysiakini that the investigation was uncalled for.

"(Denis) was only expressing his anger towards the GST and how the police handled (the protest). That does not warrant the police to start investigation papers against him.

"He doesn't belong to a party or an NGO, I don't think he can mobilise people against the police," he said.