Mental Harrasment and embarassment by Girl

She contacted me for job 4 years ago then we started chatting with each other.Then She told me that she loves me and want to marry me..But I never promised to marry her and we dont have any physical relationship..Now she came outside home in night and create scene in public..even she came my office and wait for me and when I came out from my office she catch my hand and create scene in public..I even gave a complaint to police but they told If we call her and she gave any wrong statement you will be booked for life..Her family one side says if she wants to we dont allow her to marry with you..When she comes outside my house and create a scene and I call her family then they say..If somthing will happen to her..we wont leave you..The girl is 5 year elder then me..She threat to sucide and her family threats of police case..Please suggest me how to proceed in this matter