Justin Bieber and Selena Gomez reportedly vacationed together in Mexico days before ringing in the New Year's but an insider said the trip ended with a fight and the pair broke up once again. 

A source "especially close" to the 18-year-old said the pair fought in Mexico on Dec. 30 and broke up. The insider also commented on the incident involving Chris Guerra, the photographer hit by a SUV and killed on Tuesday, Jan. 1, while trying to snap photos of Bieber's car off of a Los Angeles highway. 

Guerra thought he could spot Gomez and Bieber together. TMZ reported that the photographer allegedly called friends before he was killed saying that he saw Gomez's car in the Four Seasons parking lot. However, the source said Bieber was seen leaving the Four Seasons hotel alone on New Year's Day. Gomez never stayed at the hotel and the two pop singers have not spoken in days. 

"The two of them flew to Mexico for New Year's Eve, but had a blow-out argument on December 30 and broke up," the source said. "Selena left Mexico that same day and Justin left for L.A. on the 31st. They haven't seen each other since and she was never at the Four Seasons on New Year's Day." 

Perhaps a nod to her being newly single, Gomez tweeted on Jan. 1,  "New beginnings. Fresh start. I love you all." 

HollywoodLife.com reported that the couple did in fact spend a weekend together at a Mexican resort. An onlooker saw them arrive together at an airport in Puerto Vallarta, Mexico, on Saturday, Dec. 29. Based on Bieber's Instagram photos though, they were not alone. The "Boyfriend" singer posted a picture on Dec. 30 of him and rapper Lil' Twist "in the jungle." He also posted two photographs of himself shirtless with the caption "Vacay."

Gomez and Bieber were also spotted together days before Christmas in a Salt Lake City, Utah, airport after reportedly visiting a local ski resort. An onlooker in the airport saw Gomez sitting on Bieber's lap and the two exchanging kisses before flying home separately.

The two teens have been on and off since October 2012.

Tags: Justin Bieber Selena Gomez