The schoolgirl, aged 13, took her own life at her home in Ballybofey last Saturday.
There are claims she was being physically and psychologically bullied by other teenage girls in the Ballybofey and Stranorlar areas.
On Wednesday night a gang attacked the home of another teenage girl in the area. They poured paint over a family car and the wall of the girl’s home.
Gardaí are also investigating a second incident of intimidation at the same house on Thursday night.
“Tension in the area is extremely high,” admitted one reliable source.
“It’s just rising by the day and rather than calming down it has gotten a lot worse since Erin’s burial on Wednesday.’”
Many claims are being made on Facebook against those believed to be involved in the case.
Pupils are due to return to Erin’s school — Finn Valley College — on Monday for the first time since her death. The HSE has offered nine counsellors to the school to deal with the aftermath of the death.
Reacting to the news of the latest incidents, Lord Mayor of Donegal Frank McBrearty called for calm.
“This is not a time for people carrying out such acts,” he said.
“We must allow due process to take its course and we must allow the HSE, the board of management at the school and the gardaí to do their work.
“Nobody knows the full story surrounding this case and only the relevant authorities can get to the bottom of this situation.”