A few things explained
I'm a little more knowledgeable about Romanians and their folklore than most so here is my take on it.
There are two types of strigoi; strigoi viu (living strigoi), and strigoi mort (undead strigoi). Both types are the basis for the Bram Stoker Dracula tale, which is a western version of the strigoi mythology. So forget every vampire movie and myth you know of, they are western derivatives.
When a person dies a violent death there is a higher chance for them to become strigoi. Hence the villagers watching over the murdered man in his casket. However at the beginning of the movie when the man and his wife are killed their bodies are buried immediately and they become strigoi mort. The reason they are killed is for trying to buy up the village illegally and it is hinted at they will then sell the land to Israelis or Turks. It also appears that he choked the man in the coffin to death but instead of calling the police they murder his wife and him and loot their house. It is worth noting that the sale of land to foreigners is an ongoing problem in modern Romania.
Almost immediately the 2 people become strigoi and kill the grandfathers dog. The woman next door sees the dog being killed and eaten and faints in her doorway, which is where our protagonist finds her the next morning. She may or may not remember what happened.
The police man was killed when he went to confront the man who was killed because he did not know his wife and he had been murdered. He is bitten several times by the strigoi who had returned home and is killed. The villagers find him and bury him because they don't want the police to get involved. The policeman later rises as a strigoi himself (died a violent death) and instead of having hunger for food he craves cigarettes and canibus which he had denied himself while alive.
None of the strigoi mort are aware that they are dead. So they go right on following the motivations they had in life. IE collecting land, getting revenge on people, smoking cigarettes, eating food, etc.
Then there is our protagonist and his grandfather. They are revealed to be strigoi viu or living vampires. This was a secret of the village that was not revealed publicly because of the communist invastion and the resulting secrecy for the next 40 years under Cheaucescu. In the soviet times there were secret police, neighbors informed on each other, lands were taken away, people were 'disappeared' and it was a paranoid time where people were very secretive from each other. This is what allowed their families secret to endure.
His grandfather never sold his land because he is an immortal and he has always/will always live on that land. Several people who were able to prove their land ownership after Cheaucescu's fall were bullied into selling to the rich man who became a strigoi but refused to. So he arranged for the village preacher to gain access to their homes and steal their papers in return for the building of an ornate greek orthodox church. The villagers found out about all of this and working with the priest and using the murder of the old man as an excuse they sought to murder him and his wife, steal their posessions and then falsify the land ownership books to show that the villagers themselves owned the land.
Because of the double dealing and double/double dealing nobody wanted the police involved which is why our protagonist had such a hard time dealing with them.
The protagonist is strigoi viu but doesn't realize it. When they cut to scenes of him living in Italy he seems disgusted by the people he sees, because he is not human. He doesn't know why people disgust him they just do. This is also why he could not become a doctor. It is not mentioned if his father, mother, and siblings were also strigoi but since none of them live in the town it is presumed they are not, just his grandfather and him. Possibly because his grandfather fed on him in his youth.
There are so many little things in this movie that ring true of Romania, it was suprising given it's a british film.
1. All the actors are well known Romanian actors.
2. The funeral feast and the way visitors are plied with many kinds of food is real.
3. The neighbor lady getting sick from food and thinking it was a curse from using stolen goods takes everything she stole and returns it except for the red shirt. She attempts to fool the spirits by placing another in it's place.
4. The grandfather's rants about communists and Gypsies echo real fears that native Romanians have about the things the communists took away and roving bands of gypsies breaking in and stealing things. There is quite a lot of racism from ethnic Romanians against Roma or Gypsies. Watch a movie called Gadjo Dilo to see what I mean.
5. Many Romanians go live and work in Italy as a way to make money for their families. Similar to Mexicans living and working in the US to send money back to Mexico. When he comments about Italy "Too many Romanians" this is a hint at that.
6. Everything to do with strigoi and the burial rights of people is very authentic.
7. The music and the way it is used in the film is authentic. Everything from Korkani Orchestra and Tarif De'Haidoukus to the American band Beirut. Even the radios used in the film with the flashing lights is very Romanian.
8. Many village people in spite of living much more modern lifestyles than we would suppose, still cling to old superstitions and are still distrustful of the state, police, and government after 40 years of corruption by the dictatorship. It's not uncommon for people to take the law into their own hands to keep the police out of it.
When the truth is too painful the weak will label it a lie.
Hard Truth.