SAUGUS – A geotechnical engineer will be on site Friday to give a best-guess estimate on the stability of the collapsing retaining wall teetering above Hesper Street.Town Manager Andrew Bisignani met with department heads earlier this week to try to determine what could be done for the neighborhood.”Our main concern is public safety,” he said, adding that liability is also an issue.Bisignani said the state Building Inspector has already visited the site where a section of the 400-foot by 30-foot retaining wall collapsed, sending debris down a steep embankment and into the backyards of eight homes along Hesper Street.Hesper Street residents are looking for answers, but Bisignani is not sure he can provide them. The town walks a fine line between reaching out to the neighbors and inadvertently taking on liability. Both Bisignani and Town Counsel John Vasapolli said because the incident happened on private property, technically the town has no responsibility. If the town does reach out in any capacity other than covering basic public safety concerns, it could automatically assume all liability connected to the incident.Bisignani, however, said he could answer at least one outstanding question. Initially it was thought the four unfinished properties on Hitching Hill Road, where the retaining wall sits, were in foreclosure. He said that is not true.”We met with an attorney representing the mortgage company,” he said. “They are owned by four different individuals. It is private property, but it hasn’t been foreclosed on.”Bisignani said residents should contact the homeowners regarding liability issues – the town’s only position is making sure the public at large is not in harm’s way.”The state’s Building Inspector has been at the site and said the town is following the proper procedure,” he said.The geotechnical engineer hired by the town will begin test borings on the site Friday. Bisignani said he would also pour over all the reports connected with the project.”He’ll look at everything and come up with an educated guess basically,” Bisignani said. “It’s really the best he can do.”