Based on a tip-off, a team of Crime Branch personnel, which was investigating the case, nabbed the accused, identified as Shakeel Ahamed, police said.
Earlier eight persons were arrested in connection with the case. According to police, Ahamed, who was working as a migrant labourer in a quarry in Wadakkanchery, was with the children when they had been allegedly brought here by a train last month.
But, he had fled the scene when the railway police detained the children and those who accompanied them for not possessing valid documents, they said.
Meanwhile, Jharkhand Labour Commissioner Manish Ranjan, who visited the homes where the trafficked children are sheltered, said steps would be initiated to take over 150 children from his state to their homes.
Over 580 children from Bihar, Jharkhand and West Bengal, meant to be brought to two orphanages in the state, were detained by police at a railway station here after finding that many of them did not have any proper documents.
The issue had snowballed into a major row in the state with IUML, the key partner in UDF, objected treating the incident as a case of child trafficking.
Taking a serious note of the incident, Kerala State Child Rights Protection Commission had directed the state government to take necessary steps to send the children back home.
The children are now kept at state-run juvenile homes of the Child Welfare Society in Palakkad, Malappuram and Thrissur.