'The Killer Is One of Thirteen' is the English title of the film and that basically is the plot. It's a Spanish giallo film. A widow invites twelve people to her remote house as she suspects one of them may be responsible for the death of her husband in a plane crash. Throughout the first hour of the film there is endless talk about motives and relationships and evidence. It is hard to keep up with who is who and what is what as there are so many people to keep tabs on. Then after an hour the grisly killings begin (by someone in black gloves naturally) to liven up the proceedings and the film rushes through to the weak conclusion where all is hurriedly explained. It had potential but did not live up to it.

The characters were bland and the acting was too. The great Paul Naschy is in it but certainly not enough. He appears now and then almost randomly. As giallos go it is average.

Not a lot of nudity and little blood, this giallo is closer to Agatha Christie than Edward Wallace. That said, it does have Paul Naschy in it and it's directed by Javier Aguirre, who made Count Dracula's Great Love.

Patty Shepherd (Edge of the Axe) stars as Lisa, who has gathered twelve of her husband's closest friends and informs them that she believes that one of them is the killer. That said, there are really seventeen suspects when you add in the butler, chauffeur, maid and gardener.

All the phone lines get cut, people start getting killed off and secrets are revealed. There aren't many Spanish giallo that I can think of, other than Clockwork Terror, The House That Screamed, Blue Eyes of the Broken Doll, The Corruption of Chris Miller and A Dragonfly for Each Corpse. Come to think of it, I know way more of these movies than I thought I did.

This exciting film contains tension , thriller , drama , mystery , plot twists and shocks , including decent scares with tense killing sequences especially in its final part , in a creepy denouement . Slowly paced flick with a fairly suspenseful and horrifying story in which a killer series undergoes a killing spree by means of brutal executions . This thrilling picture concerns about some higher-class people are gathered by a widow , Lisa Mandel(Patty Shepard) , in an isolated mansion under mysterious circumstances and one by one they are murdered , each according to a peculiar relationship with Carlos Mandel , the formerly deceased husband by aviation crashing . The beautiful widow invites a number of guests to stay at her residence , these are the followings : Francis , widow's cousin (Eusebio Poncela) , his mother (Trini Alonso) , the playboy Harry Stephen (Simón Andreu) , Martin (José María Prada) and lover , Srta. Hoven (Dyanik Zurakowska) , the suspicious painter , Harlan (Jack Taylor) , Guillermo (Eduardo Calvo) , his wife Laura (Carmen Maura) , among others . Furthermore , there appears servants , gardener (Blaki) maid (Marisol Delgado) and butlers (Ramiro Oliveros , Paul Naschy) . Later on , the widow reveals that she knows that one of the group killed her husband and she is attempting to search for hubby's murderer . As he really didn't die by plane crash , but he deceased by a sleeping pill that caused the deadly accident when he was crossing the Mancha Canal . Before dying , the husband to withdraw money from the bank : 10.000 pounds , this cash is , day-present, missing . Soon they are being too murdered one by one . As they are being killed by cutting car brake line , slitting , garrotting , hanging , and stabbed in the chest . Meanwhile , at the mansion occurs the regular loving conflicts , including sexual scenes , as sex with butler , as sex with a maid , triangles , jealousy , and betrayals . As the guests are astonishing about the inexplicable deaths are happening . The premise is the following : who's the killer among the suspicious guests ?

The plot is plain and simple , regarding a group of wealthy people are invited by a widow and shortly after , realizing that they are being murdered one by one . This Giallo contains suspense , thrills , chills , intrigue and plot twists . Aguirre designs a mediocre thriller , including some regularly staged murders plenty of startling visual content with blood and gore , though was submitted to limited censorship in Spain . This is a customary slasher in which mystery , tension , suspense appear threatening and lurking in every room , corridors and luxurious interior and exterior . The picture packs atmospheric blending of eerie thrills and creepy chills combined with a twisted finale . It displays lots of blood but it seems pretty mild compared to today's gore feasts . The staged killings are the high points of the movie , they deliver the goods plenty of screams , shocks and tension . This "The Killer Is One of Thirteen" contains usual ingredients of the ¨Gialli¨ sub-genre : suspenseful intrigue , twisted killings , violence , sadism , physical abuse , and some female nudity . Based on a script by Alberto Insua , soon after Javier Aguirre adapted the screenplay . The main excitement lies in watching what new and amazing killing to be committed by a strange executioner , a black gloved killer . Sensationalist murder pieces , including by axe in the head , killed in shower , stabbing , asphyxiate , head bashed in , decapitation and grisly slashing . However , the film results to be slow-moving and extremely talking , for more of a hour , there happens nothing . The Giallo plot is mingled with the typical Agatha Christie mystery developed in her known novel ¨Ten Little Indians¨ that had several cinematic adaptations , such as 1965 rendition by George Pollock , 1975 recounting by Peter Collinson and 1989 retelling by Alan Birkinshaw . The cast is pretty good , plenty of known Spanish actors , such as : the gigoló Simón Andreu , Eusebio Poncela , Alberto Fernández , May Heatherly , Paloma Cela , Jack Taylor , Dyanik Zurakowska , Eduardo Calvo, Jacinto Molina , Ramiro Oliveros and several others .

The motion picture was regularly directed by Javier Aguirre and it has several flaws , gaps and failures . Javier Aguirre has filmed with all of the power and sensationalism at its command but in exploitation style . Father of director Arantxa Aguirre with first wife , actress Enriqueta Carballeira , being his second wife Esperanza Roy , both of whom usually play his films . Javier is a craftsman , expert on comedies such as : ¨El Astronauta¨, ¨Los Que Tocan El Piano¨ , ¨Locuras De Parchis¨ , ¨Los Chicos Con Las Chicas¨, ¨Soltero Y Padre En la Vida¨, ¨Soltera Y Madre En La Vida¨, ¨Rocky Carambola¨, ¨Martes Y Trece¨. Aguirre also made quite a few terror movies as ¨Gran Amor Conde Drácula¨, ¨Jorobado De La Morgue¨ , ¨Asesino Está En Sus Trece¨. In addition , he directed various ¨Avant Garde¨ films.