Lakhimpur Police on Friday recovered 12.41 grams of heroin filled in 96 small plastic containers from Harmutty.
The police also arrested one Raj Pegu, a resident of Ranga Reserve Forest in Lakhimpur.
In a separate breakthrough, Lakhimpur police on Thursday arrested three more robbers involved in the Chinatalya robbery case earlier this month.
The arrested have been identified as Saidul Ali, Sayid, Amzad Ali, and Zubbar Ali.
They were from their hideout in Ladrumbwai, Meghalaya.
Police also recovered Rs 78,000 cash from their possession.
All the arrested belong to Kehutoli area under Laluk Police Station of North Lakhimpur district.
With their arrest, the total persons arrested in the Chinataliya robbery case have risen to seven.
Robbers looted Rs 9 lakh cash, gold ornaments and injured one in the sensational Chinataliya robbery incident.