You will hardly ever find a complete sentence in newspaper headlines and that is not surprising. Headlines need to be short and to the point. Many headlines consist of a string of noun phrases with no verb.

More water cuts in city
LPG price hike after polls
Militants take villagers hostage

Articles and the verb be are usually left out in headlines.

Indian-American woman assaulted (Instead of ‘An Indian-American woman was assaulted.’)
Over 100 killed in blast (Instead of ‘Over 100 people were killed in a blast.’)

In newspaper headlines simple present tenses are often used instead of continuous or perfect tenses. Note that present tenses are used for both present and past events.

Terror strikes police base
Militants gun down villagers (= Militants gunned down villagers.)
Olympics put UK spy agencies under pressure. (= The Olympics has put UK spy agencies under pressure.)
Hubble spots Pluto’s tiniest moon. (= The Hubble space telescope has spotted Pluto’s tiniest moon.)

Infinitives are often used to refer to the future in headlines.

PM to visit Russia in May

In passive structures auxiliary verbs are usually dropped, leaving past participles.

Six killed in explosion. (= Six people have been killed in explosion.)

Note that past tenses are usually rare in newspaper headlines. So forms like held, killed, assaulted, detained, murdered etc., are usually past participles with passive meanings.

Compare:

UK woman assaulted and killed. (= A UK woman has been assaulted and killed.)
UK woman assaults her kidnapper. (= A UK woman has assaulted her kidnapper.)