Farhan Azmi, the son of Samajwadi Party MP, Abu Asim Azmi, detained by the Dubai police for 37 days on alleged drug charges, was released on Tuesday morning, family sources said.
The Dubai police has deported him to Mumbai.
The arrested were identified as Karan Singh Narsingh Rajit, Manoj Muddanna, Amar Bahadur Bam and Sumit Vazhakkulath Ponnappan, a senior official of the Dubai police said.
The gangster, though arrested for criminal offences, does not have any terrorism or political link cases against him in UAE, the officer said.
Rival gangster Chhota Rajan is believed to be behind the attack.
Dawood Ibrahim's brother was picked up by the Dubai police on December three in connection with a murder case of another gangster.
The National Investigation Agency will soon have in its custody key Indian Mujahideen operative Faizan Sultan accused of facilitating the travel and shelter of IM operatives from India to Dubai and then to Pakistan.
Television channels were ready to plumb below rock bottom in their frenzied prospecting for TRP gold, says Shuma Raha.
An Indian who filmed a senior Emirati official assaulting another Indian has been arrested by the police for uploading the video online that has now gone viral.
Gangster Chhota Rajan, arrested in Bali on Monday and who is likely to be extradited to India, was not one to forgive or forget easily. Mumbai's foremost crime writer S Hussain Zaidi recalls the time when Rajan was almost killed in an attack by his rival Chhota Shakeel, and how Rajan extracted revenge across continents.