Mark (17) was found near Motherwell Civic Centre at 9.30am on Sunday (July 12)
Emergency services rushed to the centre but Mark was pronounced dead at the scene.
A Police Scotland spokesperson confirmed that the death was being treated as “unexplained” and added: “A post mortem examination will be carried out in due course to establish the exact circumstances of the death.
“A 17-year-old male has been arrested and charged in connection with drugs offences.
“ He has been released on an undertaking and is due to appear at a later date.”
Mark had just finished his sixth year at Our Lady’s High School and his head teacher Dan Cardle said: ““This is a terribly sad and tragic incident. Mark was heading on on to university to study engineering.
“ Our thoughts are with his parents, family and friends who are very much in our prayers.
“This is truly heart-breaking for everyone here at Our Lady’s and in the wider school community, particularly as Mark’s life has been cut short at such as young age and with so much ahead of him.
“Mark was extremely talented and bright, a successful footballer, with a wonderful personality that made him many dear and close friends here at the school, all of whom are devastated at hearing this news”.