In a welfare society one member casts aspersion. Is it a libel suit or defamation suit?

it wont come either under defamation or libel. If a letter is sent to a person,with some false allegations, it is only that person who reads and it is not a public letter. in such a case no actionable claim lies. Further by such allegation, even though false, one must prove that his image has been tarnished and sustained damages. No suit lies. Best way to deal is to put facts before the members, and prove that the allegations are false. Except this no actionable claim lies, as it is a society not individual