19 year old Conor O'Brien was shot dead last Thursday.
A man in his 50s is being questioned in connection with the murder of Conor O'Brien in Enfield
The 19-year-old was shot dead outside his flat in the town late on Thursday.
Gardai say he wasn't known to them "in any form" and have described him as someone who "kept to himself".
Conor's funeral service took place earlier today.
A man was detained yesterday for possession of a handgun in Carlow, and is now being questioned at Carlow Garda Station in connection with Conor's death.

Missing Naas Woman Deborah Doyle Located "Safe And Well"
Kildare SF Team (one late change) vs Wexford
Average Price Of Three-Bed Semi-Detached Homes In Kildare Now Cost €400,000
Council Says Reopening Celbridge Abbey Car Park Would Hit Parking Budget
Where To Recycle Your Christmas Tree In Kildare From Next Week
Over 9,000 Tusla Referrals Linked To Poor School Attendance Were Made Last Year
Homelessness Figures Reach Another Record High, With Numbers Also Increasing In Kildare
Kildare Under Status Yellow Ice Warning From Tomorrow Evening As Temperatures Set To Plunge