A 14-year-old Manitoba boy accused of threatening students at Rivers Collegiate is now facing additional charges, including conspiracy to commit murder, following an RCMP investigation into an alleged school attack plot.Blue Hills RCMP said officers were first alerted on March 13 to an online conversation between the Rivers-area youth and a 15-year-old from Nova Scotia. Police allege the discussions began in late February and involved plans to harm students at the school.The two suspects were arrested March 16 by Manitoba RCMP and the Bridgewater Police Service in Nova Scotia.Investigators seized the Manitoba youth’s phone and other electronic devices following his arrest. RCMP later executed search warrants at two properties connected to the suspect, where officers seized additional electronic devices and other items, including two firearms owned by a relative.The boy was initially charged with uttering threats.RCMP Major Crime Services said further investigation led to new charges being authorized. Officers re-arrested the suspect Wednesday at the Manitoba Youth Centre.The youth is now charged with conspiracy to commit murder, counselling the offence of murder and two additional counts of uttering threats.Police said the accused is scheduled to appear in court June 4.