"Those,who killed in the accident, were residents of our area"
Q. Is above sentence construction is correct?
A. No. It should be either:
Those who were killed in the accident were residents of our area.
Those killed in the accident were residents of our area.
I believe these would be examples of passive voice, as active voice is characterised by the subject carrying out the verb. That is not present in this sentence.
You also asked about newspaper headlines and gave this example:
"Three members of tourist family killed in accident"
Newspaper headlines often omit words for sake of space and are not the best examples for someone learning English as a second language. News headlines have a set of rules all of their own. The example you give is typical and makes sense to me, but if it were written grammatically it would likely say:
Three members of a tourist family have been killed in an accident.
If you read the article beneath the headline you will find that it almost certainly expands on the headline in a proper grammatical way.