Delilah Terriak asked anyone who may have seen Loretta Saunders or her blue car to contact police, adding that she and dozens of supporters planned to plaster the city with posters bearing pictures of the missing 26-year-old.
"She is so strong and that's what's keeping me going through this — knowing that she wouldn't want us wasting time crying," she said at a native friendship centre in Halifax.
"If I were missing, she would be doing the exact same thing, probably even more. ... She is my world, she's my everything."
Terriak, who flew to Halifax from British Columbia to search for Saunders, is also appealing to the public for financial help to bring her five brothers and parents from Labrador to help locate the Saint Mary's University student who was last seen on the morning of Feb. 13 in the Cowie Hill Road area of the city.
Terriak says her sister is set to graduate from university in May and is doing her thesis on missing and murdered aboriginal women.
Saunders's car was found earlier this week near Windsor, Ont., and Halifax police issued arrest warrants for Blake Leggette, 25, and Victoria Henneberry, 28.
Ontario Provincial Police arrested Leggette and Henneberry earlier this week on charges of possession of stolen property, which were stayed during a court appearance Friday in Windsor.
One of their lawyers said they were also remanded for six days to give authorities from Nova Scotia time to bring them to Halifax.
"There has been a warrant issued out of Nova Scotia for the theft of the vehicle, so the justice of the peace signed an order holding both accused in custody for up to six days," defence lawyer Maria Carroccia, who is representing Leggette, told CKLW radio.
A provincial court document filed by Halifax police alleges the pair, who live at the same apartment on Cowie Hill Road in the city, stole the 2000 Toyota Celica that belongs to Saunders.
Terriak said her family needs to be together in Halifax as the search for Saunders continues.
"My family is having a difficult time processing what's going on and having a hard time finding answers," she said in a prepared statement released at the news conference.
Annie Clair, 43, met Saunders just before she disappeared and was due to be interviewed by her as part of her thesis. She said Saunders wanted to talk to her about native traditions, the language and aboriginal women.
"She wanted to learn because she didn't have that part of her growing up," she said. "She is an amazing person, she has a good heart and she was really interested in knowing the traditional ways."
Clair, who lives in Elsipogtog, N.B., said she was shocked to hear that Saunders had disappeared and urged people to help in the search, saying there is added urgency because Saunders is three months pregnant.
"It's very important that we do find her," she said at the centre, where the scent of burning sweet grass wafted around people seated at a table and putting together posters of Saunders.
Const. Pierre Bourdages of Halifax police has said Leggette and Henneberry know Saunders, but he declined to provide further details on the nature of their relationship.
Police have said they don't know exactly how the car ended up in Ontario, but they are asking anyone who may have seen Saunders or her car, with a Newfoundland and Labrador licence plate of HCP 543, to come forward.
Police say Saunders is five-foot-seven and about 120 pounds with light brown straight hair.
(The Canadian Press, CKLW)
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