The subject is the noun brahmano (holy man, nominative singular). The verb is yati (goes, 3rd person, singular, active, indicative, present tense). The object is the adjective anigho (undisturbed, nominative singular). There are two clauses dependent on this main sentence: 1) mataraj pitaraj hantva rajano dve ca khattiye (having killed mother, father and two warrior kings). The subject is omitted, implying the subject of the main sentence, the noun brahmano. The verb is in gerund, hantva (having killed). There are three objects, the nouns mataraj (mother, accusative singular), pitaraj (father, accusative singular) and rajano (kings, accusative plural). This last word has two attributes, the noun khattiye (warrior, accusative plural) and the numeral dve (two, accusative plural). The conjunction ca (and) connects the last object to the two preceding ones. 2) ratthaj sanucaraj hantva (having killed the whole country with its followers). The subject is omitted, implying the subject of the main sentence, the noun brahmano. The verb is in gerund, hantva (having killed). The object is the noun ratthaj (country, accusative singular). It has an attribute, the adjective sanucaraj (with followers, accusative singular).
Once a group of monks visited the Buddha. While they were paying their respects, the monk Lakuntaka Bhaddiya, who was an Arahant, passed by. The Buddha told the monks this verse (and the following one, DhP 295). He told the monks to look at Lakuntaka Bhaddiya: he was a monk who has killed his parents, and kings, indeed the whole country; and yet he was walking calmly, without remorse. The monks could not understand what the Buddha was talking about! Surely this Arahant had killed nobody! Then the Buddha had to explain: "mother" means craving, "father" is conceit, "two warrior kings" are views of eternalism and nihilism, "the country" are sense-organs and sense-objects and the "followers" are attachment and lust.