The four are G Thalapathi, N Suresh Babu (DMK executive ccommittee member) KrishnaPandi and Kodi Chandrasekharan.
Speaking to reporters after meeting them, Alagiri said they are his close friends and and he had come to see them.
He also referred to his father and DMK chief M Karunanidhi's remark that false cases had been foisted against them."I only called on my friends. Nothing else," he said.
Suresh babu was also Alagiri's political Personal Assistant. Former ministers I Periasamy and K K S S R Ramachandran were among party leaders who accompanied Alagiri.
The four were arrested yesterday on a land grabbing complaint filed against them by a woman of nearby Sengulam village.
The complainant said the four had threatened and forced her to sell their 5.14 acres for a cheap rate. She was paid only Rs 40 lakh for the land costing Rs 4.36 crore and forced to sign a power of attorney in July last year when DMK was in power.